Monday
December 5, 2016

Posts by Graham

Total # Posts: 425

Algebra II
Let's start here: "Write an equation to determine how far she can drive based on the gallons of gas in her car." So when we write an equation, there's usually an independent and dependent variable. In this case, how far she can drive DEPENDS ON the gallons of...
September 14, 2016

geometry
Do what two recipes? You'll have to be more specific.
September 14, 2016

Math
So, she has 5.5 pounds and wants to split it into 50 bags. This is a division problem. She wants to divide 5.5 pound into 50 bag: 5.5 / 50 Since this is a fraction as well, she could divide both 5.5 and 50 by 5 (same thing as multiplying by (1/5)/(1/5) or 1): (5.5 / 5) / (50...
September 14, 2016

math
No, you didn't waste my time, understanding is an important part of learning.
September 14, 2016

math
So, J = 4, and we have the equation: s + j = 17 You can solve this by substituting 4 for j in that equation.
September 14, 2016

math
First of all, don't start a new post every time you ask, reply to the same original one. I assume you're referring to the problem where I answered: "Sam's age is five years more than twice Jessica's age." So, Sam's age, which I will designate a &...
September 14, 2016

MAth
Well, do you know what a function is? A function is an equation where every input has only one output. In notation, x is the input. So the question is really asking: "Can x equal anything in following equation which will result in multiple y-values?" The best way to ...
September 14, 2016

Algebra
Yeah, if it's coefficient, it's definitely "of". Crossword puzzles are really not the best way to understand math concepts anyway.
September 14, 2016

Algebra
Ok, so we've got: _ _ E _ _ _ _ _ _ T My best guess is "Coefficient", given the context, although that is 11 letters.
September 14, 2016

math
No, that is not correct. If you want better help, show whatever work you've done on the problem. That will help me understand where you aren't understanding. And I've already answered this question twice.
September 14, 2016

Math/Algebra
If that is the case: Refactor the denominator (bottomm), and you'll get the right answer.
September 14, 2016

Math/Algebra
I'm assuming the original equation is: (Z^2 - 8Z + 12) / (Z^2 + Z -6) So, that 8 is actually an 8Z, right?
September 14, 2016

math
I already answered this in the previous question, but here it is again: "Sam's age is five years more than twice Jessica's age." So, Sam's age, which I will designate a "s" is 5 years more than twice Jessica's age, which I will designate as...
September 14, 2016

math 101
Ok, so first, n + 2 > 8 can be simplified: n + 2 > 8 n + 2 - 2 > 8 -2 n > 6 and the replacement set for the variable is all one-digit prime numbers To answer that, we have to know the 1 digit prime numbers, which are {2, 3, 5, 7}. So n can equal any of those ...
September 14, 2016

math
"Sam's age is five years more than twice Jessica's age." So, Sam's age, which I will designate a "s" is 5 years more than twice Jessica's age, which I will designate as "j". From this we can realize that twice Jessica's age (2j...
September 14, 2016

World History
The assignment sounds like two stories: the headline article, which would be on the front page in a real newspaper, and the international article, which could fill up other space that the headline article doesn't fill up, and perhaps continue onto another page. If you ...
September 14, 2016

Math
So, you know the values of a, b, and c. You have an expression with the variables a, b, and c. Because you know what each variable equals, you can substitute each number for its respective variable. The expression is: a - b + c = And, a = -2 (-2) - b + c = You can then ...
September 14, 2016

Pre algebra
That should be right, as long as the first term is "2st^2" and not "(2st)^2".
September 14, 2016

Math Help
"8 less than y" What is would you do to y to get 8 less than y? "is 2" Is means equal in this context. So, 8 less than y = 2
September 14, 2016

maths
How many Sq metres is there in a area of 200cm x195cm x10cm deep?
November 20, 2015

science
If the absolute temperature ooh 6 inches cubed of a gas decreases by a factor of 2, what will be the new volume? How do set up this problem and solve it?
November 18, 2014

Maths
the length of a rectangle L metres and the width of the rectangle is W metres. Each measurement is correct to the nearest cm. Find, in terms of L and W the difference between the lower bound and the upper bound of the area of the rectangle.
November 12, 2014

physics
A 2.41 kg ball is attached to a ceiling by a 1.86 m long string. The height of the room is 3.38 m. The acceleration of gravity is 9.81 m/s 2 . What is the gravitational potential energy associated with the ball relative to a) the ceiling? Answer in units of J b) the floor c)a ...
December 6, 2013

Calculus
Find the number b such that the line y = b divides the region bounded by the curves y = 4x2 and y = 1 into two regions with equal area. (Round your answer to two decimal places.)
November 18, 2013

math
Let the folders cost f. Let the rulers cost r. Sarah paid: 8f + 3r Lea paid: 8r + 3f Sarah paid 1.25 more than Lea. 8f + 3r = 1.25 + 8r + 3f 5f = 1.25 + 5r f = 0.25 + r The rulers cost: r = 0.45 .: f = 0.70 Each folder costs 70 cents. Check. 8*(0.70) + 3*(0.45) = 6.95 1.25 + 8...
November 1, 2013

Physics
A satellite moves in a circular orbit around the Earth at a speed of 5.3 km/s. Determine the satellite’s altitude above the surface of the Earth. Assume the Earth is a homogeneous sphere of radius 6370 km and mass 5.98 × 1024 kg. The value of the universal ...
October 29, 2013

algebra
Redistribute for like terms. = (8+8)m3+(-3+3)m2+(1-4)m+(-5-2) = ...
October 10, 2013

Calculus
f(x) is continuous over the domain. [-3,3] f(x) is differential. f'(x) = 3x2 -9 f(x) has two equal value points on the independent axis. f(-3) = f(3) = 0 Therefore Rolle's Theorem Applies .: Exists c such that f'(c)=0 Solve for c: 0 = 3c2 - 9 ...
October 10, 2013

Physics
The centre of gravity is the point around which the weighted distribution of mass of the body sums to zero. Its relative placement within the body is independent of the orientation of the whole body; though of course it is affected by redistribution of parts of the body. ...
October 9, 2013

Math-Algebra
Again, use Pythagorus. d2 = 152 + 152 d = 15√2
October 9, 2013

Math-Algebra
Use Pythagorus. 122 = 22 + h2
October 9, 2013

Chemistry
Use: E = hc/λ Where: Planck Constant: h = 6.62606957(29)×10−34J∙s Speed of Light: c = 2.99792458×10+9m∙s-1 Wavelength: λ = 0.130m
October 8, 2013

math
a) S'(t) = dS(t)/dt S'(t) = ((d5t/dt)(t2+1) - 5t d(t2+1)/dt)/(t2+1)2 S'(t) = (5(t2+1) - 10t2)/(t2+1)2 S'(t) = (5-5t2)/(t4+2t2+1)
October 6, 2013

Physics
m1 × 3.10m/s2 = m2 × 2.00m/s2 m2 = 1.55 × m1
October 6, 2013

chemistry
Use V = m / (w c) Where: V : volume m : mass w : molecular mass c : concentration
October 6, 2013

Calculus
Don't forget the constants of integration. ------------- A = ∫ √(a2-x2) dx Let x = a sin(θ) dx = a cos(θ) dθ A = ∫ a2cos(θ)√(1-sin2(θ)) dθ A = ∫ a2cos2(θ) dθ A = (a2/2) ∫ (cos(2θ)+1) dθ A...
October 3, 2013

Calculus
(B) You have two simultaneous equations in two variables. The original equation, and the derivative for specified values of dy/dx. When dy/dx=1/2 : 1/2 = y/(2y-x) Rearrange: 2y - x = 2y Hence: x = 0 Substitute back into y2 = 2 + xy: Therefore: y = ±√2 Answer: (0...
October 2, 2013

Chemistry
Compare to the tossing two coins. P(Head ∩ Head) = P(Head) × P(Head) = 1/4 P(Head ∩ Tail) = 2 × P(Head) × P(Tail) = 1/2 P(Tail ∩ Tail) = P(Tail) × P(Tail) = 1/4 (Note that there are two ways to toss a head and a tail.) The formation of...
October 1, 2013

MATH
Which of what following? ... And what do you think is the right one?
October 1, 2013

Pre-Calculas 11
I cannot see the diagram, so I am going to assume the new fencing is formed into an 'E' shape, with the opening pressed up against the existing fence line. That is: one long side (l), two short sides and the divider (3w). The fence length is: 800 = 3w + l So the area ...
October 1, 2013

la sallle
Three consecutive even integers are: 2n, 2n+2, 2n+4, where n is an integer. The rule is thus: 2(2n+4)/2n = (3/5)(2n+2) - 3 Rearranging gives: 0 = 6 n2 - 19n - 20 Find the integer root(s) of this quadratic. Solve for integer n. Use n to find the three consecutive even numbers.
September 30, 2013

maths
y = 7x + 21 a = 7*8 + 21
September 30, 2013

maths
Hint: The first sequence is: 1/(1+1), 2/(2+1), 3/(3+1), 4/(4+1)
September 30, 2013

Dice Probability
No. The probability of the first die rolling a 2 is 1/6. The probability of the second die rolling a 3 is 1/6. The combined probability is 1/36.
September 30, 2013

Card Probability
There are 52 cards in the deck; 13 in each of the four suits, and two of the suits are red. The four face cards in each suit are: jack, queen, king, and ace. P(face card) = 4/13 P(red) = 1/4 The events are independent. The probability of an intersection of independent events ...
September 30, 2013

Probability With Cards
The events are independent. Use: P(Ki ∩ ♥) = P(Ki)×P(♥)
September 30, 2013

maths
Hint: the sequence is: 21,22,23,24,25,...
September 30, 2013

MATH
Let N = a.bcd c = d+3 -> 3 ≤ c ≤ 9 b = c-2 -> 1 ≤ b ≤ 7 a = b+c a = 2c-2 -> 4 ≤ a ≤ 8 c = (a+2)/2 -> 3 ≤ c ≤ 5 .: c = 3, N= 4.130... c = 4, N= 6.241... c = 5, N= 8.352... Though of course the rules only fix the first ...
September 30, 2013

chem-redox
Opps. Cut and paste error. 2 Ca + Cr2O72- + 14 H+ = 2 Ca2+ + 2 Cr3+ + 7 H2O
September 29, 2013

chem-redox
In acidic aqueous solution you use water to balance oxygen and hydrogen cations to balance hydrogen. Ca = Ca{2+} + 2 ē Cr2O7{2-} + 14 H{+} + 6 ē = 2 Cr{3+} + 7 H2O ===================================================== 3 Ca + Cr2O7{2-} + 14 H{+} = 3 Ca{2+} + 2 Cr{3...
September 29, 2013

physics
Hint: What affect does horizontal velocity have on vertical fall? Use: vector displacement equation. x(t) î + y(t) ĵ = [x(0) + u(0)t] î + [y(0) + v(0)t - ½ gt^2] ĵ xt î + yt ĵ = (x0 + u0 t) î + (y0 + v0 t - ½ g t2) ĵ
September 29, 2013

Math
Check the bracket placement. ±√(10/3) = ±√(10)/√(3) = ±√(30)/3 = ±(⅓)√(30)
September 29, 2013

Chemistry
An ionic exchange reaction only occurs when dissolved ions are removed from solution as (1) a precipitate (solid), (2) a gas, or (3) form a molecule that remains in the liquid phase. Sodium- and Potassium- -Biphosphates (and -Phosphates) are soluble. Sodium- and Potassium- -...
September 29, 2013

Math
When y = 0 then x = 1. As y rises towards positive infinity, x rises towards positive infinity. As y falls towards negative infinity, x falls towards 0. There is no real value of y corresponding to any negative value of x. -∞ ≤ y ≤ +∞ 0 ≤ x ≤...
September 29, 2013

Computer Science
The main should declare and load the list structure (or object), and also a variable to hold the result. The list structure cannot be fixed length; it needs to grow arbitrarily long. You'll also need a way to input numbers into the list. Given your modular design, this ...
September 28, 2013

Calculus & Vectors
Use z = x + yi Plot on the Cartesian (x,y)-plane a) Plot (x, y) = (2, 0) b) Plot √(x^2 + y^2) = 2 c) Plot (x, y) = (5, 4) d) Plot (x, y) = (√2, -√2)
September 28, 2013

math
Yes. Exactly. (x^2 -7x -8) / (x+1) = x + (-8x -8)/(x+1) = x -8
September 28, 2013

math
Do you mean: 4 (x^2 + x) / (x-3x) = -2 (x+1) = -2x -2
September 28, 2013

math
Please be clearer. What does the bracketed 4 mean? Is everything to the right of the division sign on the denominator, or just the first x?
September 28, 2013

Math
Consider the quadratic: 9z^2 - 148z + 64 Its roots are: (148 ±√(21904-2304))/18 = (148±140)/18 .: either 4/9 or 16 Thus we can factorise the quartic: 9x^4 - 148x^2 + 64 = (9x^2 - 4)(x^2 - 16) Next, factorise each of these two quadratic terms in turn.
September 28, 2013

physics
Rearrange the equation: A = F_x / t^2 Then simply substitute the numbers: .: A = (781.25/1.45^2) N/s^2 Answer in three significant figures.
September 28, 2013

Science
You simply need to express 2.16 micrometres in 5.0 seconds as some kilometres per hour, retaining the appropriate number of significant figures during conversion. 1 μm = 1×10^–6 m 1 km = 1×10^+3 m 1 hr = 3600 s 2.15μm / 5.0s = _._ ×10^__ km/hr
September 27, 2013

Physics
Use the classical mechanic equations of force, displacement, and velocity under constant acceleration from rest. (1)... F = m a (2)... s = a t^2 /2 (3)... v = a t From (1), doubling the force will double the acceleration (for the same mass). From (2), doubling the acceleration...
September 27, 2013

Significant figures
The count of significant figures for the product is the least count of significant figures of the terms. To determine how many significant figures to use, count the significant figures of each of the terms and use the least one.
September 27, 2013

chemistry
(CH3)2NH + H2O = (CH3)2NH2{+} + OH{-} Kb = [(CH3)2NH2{+}] [OH{-}]/[(CH3)2NH] At 11.98 the contribution of OH{-} concentration from dissociated water is negligible. [OH{-}] = 10^(11.98-14.00) [(CH3)2NH2{+}] = [OH{-}] [(CH3)2NH] = 0.164M - [OH{-}] Kb = [OH{-}]^2 / (0.164M - [OH...
September 27, 2013

AP CHEM
This question is incomplete. It contains insufficient information to answer.
September 26, 2013

Combinatorics
C(4,1) C(5, 1) C(6, 1) = (4!/1!3!) (5!/1!4!) (6!/1!5!) = ...
September 26, 2013

Math
x ≤ -1
September 25, 2013

Math
6 ≤ 4 + (-2x) 2 ≤ -2x x ≤ 1
September 25, 2013

chemistry
You have 5.6 mL of NH3. There are 22.4 L per mole of gas at STP. So 5.6e-3 / 22.4 mole of NH3. Balance the equation to determine the corresponding number of H2.
September 25, 2013

calculus
ln(2) = 0.69314718... (A) P(6)/P(0) = 2 .: k_g = ln(2) /6mth (B) P(3mt) = 4000 e^{3 k_g} (C) k_d = -ln(2) /10day
September 25, 2013

physics
Given: v1 = 34.5 [cos(50°) W + sin(50°) N] km/hr v2 = 16.1 [0 W + 1 N] km/hr Let: s = 3 v1 + 0.5 v2 Find: |s| s = (3*34.5*cos(50°)) W + (3*35.6sin(50°)+0.5*16.1) N |s| = √((3*34.5*cos(50°))^2 + (3*35.6sin(50°)+0.5*16.1)^2)
September 24, 2013

calculous
cannot see figure.
September 24, 2013

physics
The same current flows through the same cross-sectional area, but with only half the diameter, P has only ____ the area. Thus it passes ___ the current. [If you halve the diameter what happens to the area?]
September 24, 2013

Chemistry
You also need the molar mass of water. Let x represent the amount of sodium sulfate in the sample. Solve these simultaneous equations: 142.05 x + 18.015 nx = 8.5 18.015 nx = 4.776
September 24, 2013

vector physics
Using the standard orthogonal unit vectors î and ĵ. Momentum of the system: 0.045*9.0 î - 0.145*7 ĵ kg∙m/s Magnitude: √((0.045*9.0)^2 + (0.145*7)^2) kg∙m/s Direction: angle measured off x-axis -arctan((0.145*7)/(0.045*9.0))
September 23, 2013

Physics
If a 100%-efficient engine transfers 100% of the fuel's energy to work then, 0% of the fuel's energy would be wasted as heat, vibration, or otherwise. If it extracts 100% of the available energy from the fuel then anything left will have 0% available energy; that will ...
September 22, 2013

math
Let the number of Zerg be z, and Borges be b. Heads: 45 = z + 4b Feet: 55 = 3z + 2b Solve the simultaneous equations. Hint: multiply the first by 2 and subtract the second, then simplify. Hint 2: multiply the second by 3 and subtract the first, then simplify.
September 22, 2013

math
Let the number of Zerg be z, and Borges be b. Heads: 45 = z + 4b Feet: 55 = 3z + 2b Solve the simultaneous equations. Hint: multiply the first by 3 and subtract the second, then simplify. Hint 2: multiply the second by 3 and subtract the first, then simplify.
September 22, 2013

physics
Solve for t to find the breaking time. 0 = 19m/s - t_b 4.6m/s^2 Substitute to find the breaking distance. d = t_b 19m/s - t_b^2 2.3m/s^2 Find the time to travel to that point. t_d = (48.2m - d) / 19m/s.
September 22, 2013

Physics
Given: speed of v = 30[m/s] radius of r = 25[m] Use: Centipetal-acceleration of: a_c = v^2/r
September 22, 2013

Chemistry- that is correct.
Yes. 34m/s = 34m/s * 1000mm/m * 60s/hr = 2040000mm/hr ≈ 2.0×10^6mm/hr
September 22, 2013

Physical Chemistry
∫ β δT = ∫ 1/V δV Since β independant of T, ∫ β δT = βT + constant. βT = ∫ 1/V δV Use ∫ 1/x dx = ln(x) + constant βT = ln(V) + constant .: V = k e^(βT)
September 22, 2013

Science
Let u be the horizontal speed and v the vertical. u(0)=8.0m/s, v(0)=0m/s Let x be the horizontal height and y the vertical. x(0)=0m, y(0)=20m y(t) = y(0) + v(0) t -(9.81/2) t^2 Find t when y(t) = 0m So: 0m = 20m - 4.905(m/s^2) t^2
September 22, 2013

Algebra
If n is the least of the three consecutive odd numbers, the others are: n+2, n+4. So: 5(n) +35 = 2(n+2+n+4) Solve for n, then find 3n+6
September 22, 2013

Math
A(x+5)+2(−Bx+2) = (A-2B)x+(5A+4) So: (A-2B) = 17 (5A+4) = 219 Solve the second for A, substitute into the first and solve for B, then find A-B.
September 22, 2013

Math
b + 2c = 859¢ b + 2d = 951¢ b + c + d = ((b + 2c) + (b + 2d))/2
September 22, 2013

Science/ Chemistry
P: 30.973762(2) O: 15.999(4) Ratio of O to P is: ((0.967-0.422)/0.422)*(30.973762/15.999) = 2.50 The empirical formula is correctly derived from the given masses. The empirical equation also balances.
September 22, 2013

Chemistry
Three times as many.
September 22, 2013

Discrete Mathematics
Consider that for any integer (n), (2n+1) is an odd number. By expansion and collecting terms, (2n+1)^2 = ______. Since _______ is an integer it follows that (2n+1)^2 is odd. Therefore the square of any odd number is also an odd number.
September 22, 2013

Discrete Mathematics
An argument is valid if and only if its conclusion is entailed from its premises, A valid argument is not necessarily sound. That is, the premises do not need to be true. Hence you only need to examine the form of the argument, not the soundness of the premise. The form is as ...
September 22, 2013

Chemistry
Exchange the acidic proton.
September 22, 2013

Math
find: a) carlo's speed in the last part of the journey. Carlos travels 16km at 20kph for: 20/16 hours. Thus Carlos travels the remaining (35-16) km for (2-20/16)hours at: (35-16)/(2-20/16)kph. b) the time when Arnold reaches town A. Arnold travels 35km at 25kph for: (35/25...
September 22, 2013

Math
distance = speed multiplied by time. Measure all distance in kilometres and all time in hours. The car travels: c(t) = 40 t The bus travels: b(t) = 56 (t - 0.5) Solve for t when c(t)=b(t)
September 22, 2013

Math
Parallel lines have the same gradient. The gradient of the first line is: 4/7 The gradient of the second line is: -9/m Thus: 4/7 = -9/m Solve for: m = ...
September 22, 2013

Math
2. Profit of n items made and sold is: P(n) = (45.00-30.00)n - 1200.00 a. Find n when P(n)=0 b. Find: -P(400) (Loss is negative profit) c. Find: P(1000)
September 22, 2013

Math
1. The area of a parallel trapezoid is half of the product of the height and the sum of the lengths of the parallel sides. The height is difference between the projections of A and B on the y-axis. (Ie: 5-2) The length of each side is the difference between the x-axis ...
September 22, 2013

Math
Let the scores be x, y, z. Solve the three simultaneous equations: x + y + z = 225 x + y = z + 61 x = y + 6 Start by substitution: x=y+6 2 y + z = 219 2 y = z + 55 et cetera...
September 22, 2013

Chemistry
Use Nt/N0 = e^{-kt} 1[yr] = a = 31557600[s] (1/2) = e^(-kh) Where: Half life: h= 4.5e9 * a = 1.420092E+17[s] k = -ln(0.5)/1.420092E+17 .: k = 4.8810019E-18[/s] Okay, so far. To continue... Assume there is n atoms of U238 in the sample. t=1 second latter there is n-29. (via 29 ...
September 22, 2013

algebra
The sum is this: X = (1/5 + 1/4 + 1/3 + 1/6)*X + 12 X = (57/60)*X + 12 Simplify and solve for X
September 22, 2013

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