# Posts by Scott

Total # Posts: 1,985

**Algebra**

u = t + 7 10u + t = 3(10t + u + t + u) ... = 33t + 6u 4u = 32t solve the system by substitution or elimination

*February 16, 2017*

**math**

x (154) + (40 - x)(170) = 40 (160)

*February 16, 2017*

**Math**

v / 125 = [v / (125 + 25)] + 4/3

*February 15, 2017*

**Physics**

1) the sound goes over and back ... 2 w =5.7 * 343 2)velocity = frequency * wavelength ... v = (2.22 / 7.59) * .168 m

*February 15, 2017*

**Physics**

3 s measures the km to the lightning 5 s measures the miles

*February 15, 2017*

**Algebra**

(k - 10)(k - 2) (2x + 7)(3x - 2)

*February 15, 2017*

**maths**

45 * (1 + .10)^20

*February 15, 2017*

**too-hard probability sir damon/reiny/steve help**

"you can lead a horse to water...but you can't make him drink"

*February 15, 2017*

**too-hard probability sir damon/reiny/steve help**

this is binomial...with a twist P(b) = .4 , P(w) = .6 (b + w)^4 b^4 + 4 b^3 w + 6 b^2 w^2 + 4 b w^3 + w^4 P(w ? 0) = 1 - P(b = 4) = 1 - .4^4 P(b = 2) = 6 * .4^2 * .6^2 divide to find the conditional

*February 15, 2017*

**Physics**

the given data is unrealistic please check it

*February 15, 2017*

**physics**

the ball is uniformly accelerated by gravitational force the velocity is zero at the peak 1.5 s before the peak, the velocity is ... 1.5 * g upward 1.5 s after the peak, the velocity is ... 1.5 * g downward

*February 14, 2017*

**PreCalc**

18 t + 5 t - 5 = 12

*February 14, 2017*

**Algebra 2**

x y = k

*February 14, 2017*

**Algebra 2**

the job takes 96 people-hours so for 3 people... 96/3 hr

*February 14, 2017*

**Exponential Equation**

4E12 = 24 * e^388r ln(1.7E11) / 388 = r

*February 14, 2017*

**Math**

3 1/2 is 28 eighths

*February 14, 2017*

**Math**

the scale is logarithmic 10^(8.3 - 6.2)

*February 14, 2017*

**Geometry**

the four given sides sum to 24 so the 5th side is 6 ... 30 - 24

*February 14, 2017*

**Algebra**

x + 2y = 150 x + 4y = 260 solve the system

*February 14, 2017*

**physics**

the net force is ... f = m a ... f = 111.5 * 2.7 net force is tension minus gravity t = 111.5 (9.8 + 2.7)

*February 13, 2017*

**Chemistry**

2 KClO3 ---> 2 KCl + 3 O2 moles O2 = 3/2 * moles KCl moles KCl = mass KCl / molar mass KCl mass O2 = moles O2 * molar mass O2

*February 13, 2017*

**chemistry**

find grams of C in CO2 and grams of H in H2O convert the grams to moles (divide by the molar masses) the mole ratio will give you the empirical formula

*February 13, 2017*

**college algebra**

h = 1/2 g t^2 + v t + Ho 44 = -4.9 t^2 + 20 t + 37 solve the quadratic for t

*February 13, 2017*

**Math! Please help!**

15 ? -k/4 - 9 24 ? -k/4 96 ? -k ... -96 ? k

*February 13, 2017*

**Chemistry**

381 pm is the edge length of the cubic unit cell the atomic radius is the edge length multiplied by ... ?2 / 4

*February 13, 2017*

**Math**

2 is 12/6 so you need the lowest common multiple of 12 and 5 ... 60 60/6 = 10 ... five 2 lb bags

*February 13, 2017*

**math**

looking at the cross section, this is a circle in an equilateral triangle

*February 13, 2017*

**math**

looks good

*February 13, 2017*

**math**

plug the points into the general equation and solve the system P...1 = a - b + c Q...1 = a + b + c R...6 = 25a + 5c + c

*February 13, 2017*

**math**

P and Q are the same point need 3 DIFFERENT points

*February 13, 2017*

**Chemistry**

22.4 L/mole ... gas at stp octane is 114 g/mole 2 C8H18(g) + 25 O2(g) ---> 16 CO2 (g) + 18 H2O(l) (39.0 / 114) * 12.5 * 22.4 L

*February 12, 2017*

**physics**

work = force * distance f = 5497 / 22.1 a = f / m = 5497 / (22.1 * 3090) d = 1/2 a t^2 ... t = ?(2d / a) v = a t

*February 12, 2017*

**Algebra**

3a + 9c = 183 ... 6a + 18c = 366 6a + 13c = 276 subtract equations to eliminate a solve for c, then substitute back to find a

*February 12, 2017*

**Algebra**

(r + 3) / 79 = r / 15 15 r + 45 = 79 r

*February 12, 2017*

**sciance**

depends on the car

*February 12, 2017*

**Physics**

yes the up-thrust (bouyancy) is a function of the VOLUME of liquid displaced

*February 12, 2017*

**grade7 math**

the rectangle with the least perimeter is a square

*February 12, 2017*

**Chemistry**

you aren't given the atomic mass not enough data for a solution

*February 11, 2017*

**Chemistry**

the volume of hexane is ... 338 g / .66 g/mL the height of the liquid is ... (hexane vol) / (? *2.91^2)

*February 11, 2017*

**physics**

energy = 1/2 m v^2 energy / time = power

*February 11, 2017*

**Algebra 2**

a^b = 3^3 3^(1/2)^x = a^(1/6) 3^3^x = a 3^3 = a^(1/x) x = 1/b

*February 11, 2017*

**math**

the slope is the same everywhere on the line slope = (-5 - 7) / (-5 - 4)

*February 11, 2017*

**math**

the distance is constant, so speed and time are inversely proportional t / 28 = 65 / 78

*February 11, 2017*

**Math**

c (100% - 56%) = 202.92

*February 10, 2017*

**Math**

m = [(91 - 44.39) / 44.39] * 100%

*February 10, 2017*

**physics**

how thick is the ice?

*February 9, 2017*

**math**

adding equations to eliminate e ... 3d = 12 solve for d, then substitute to find e

*February 9, 2017*

**Math**

3.36E6 poeple / 3 per household = ... 1.12E6 households 2 bags per month = 24 bags per year ... 10 lbs per bag 1.12E6 * 24 * 10 = ?

*February 9, 2017*

**Math**

a square m is 10000 square cm

*February 9, 2017*

**chem**

it will appear that there are more moles of solute than are actually present you will be dividing the mass of added solute by too large a number ... this will result in the molar mass being too low

*February 9, 2017*

**geometry**

the two angles sum to 180º x + (4x + 50) = 180

*February 9, 2017*

**Chemistry**

that's what you start with ... some of it is precipitated out also, the volume of the solution is more than doubled (remaining PbCl2) / solution volume

*February 9, 2017*

**Science ms sue please help**

the question specifies "chemical property"

*February 9, 2017*

**Science ms sue please help**

if there is no reaction...what are you observing?

*February 9, 2017*

**algebra**

c + r = 4.5 14c + 8r = 51 solve by substitution or elimination

*February 9, 2017*

**Mathematics**

x = -3 (y + 1) x^2 = 9 (y^2 + 2y + 1) substitute and solve for y there will probably be two solutions ... the intersection(s) of a circle and a line

*February 9, 2017*

**Algerbra**

the vertex is on the axis of symmetry ... x = -b / 2a f(x)=x^2+2x-3 ... x = -2 / 2*1 = -1 f(x)=x^2-3x+1 ... x = - -3 / 2*1 = 3/2 plug the x's into their functions to find the y's for the vertex coordinates

*February 8, 2017*

**math**

sin(0) = 0 ... sin(90) = 1 so ... sin(50) > sin(40) cos(0) = 1 ... cos(90) = 0

*February 8, 2017*

**Chemistry**

there are 1000 L in a cubic metre so the density is 3000 g/L the molar mass is 44.956 g so one L contains ... 3000 / 44.956 moles the number of unit cells is half the number of atoms the volume is ... 1 L / [(3000 / 44.956) * 6.02E23 / 2]

*February 8, 2017*

**math**

d = 3 q 10 d + 25 q = 385 solve the system using substitution or elimination

*February 8, 2017*

**Further Mathematics**

11th term is 10 cr from 1st term 7 * 3^10

*February 8, 2017*

**Math**

-5 = -a + b - c y' = 3a x^2 + 2b x + c ... 4 = 3a - 2b + c y" = 6a x + 2b ... 0 = -6a + 2b 3 equations, 3 unknowns ... solve the system

*February 8, 2017*

**mATH**

520 X [1 + (0.04/12)]^60 IS THIS RIGHT WAY TO DO THIS just clarifying

*February 8, 2017*

**Physics**

150 kN to pull 12 cars to pull one car ... 150/12 kN

*February 8, 2017*

**physics**

momentum is conserved (75 * 2) + (50 * v) = 0

*February 8, 2017*

**Math**

x * x * (x - 3) * (x + 1)

*February 7, 2017*

**Chem**

reacts with water to form sulfuric acid this is the "acid rain" reaction

*February 7, 2017*

**Math**

it's an even power regardless of the sign of x, f(x) will always be positive

*February 7, 2017*

**Math**

h + c = 160 ... 200 h + 200 c = 200 * 160 500 h + 200 c = 369 * 160 subtract equations to eliminate c solve for h, then substitute back to find c

*February 7, 2017*

**Mathematics**

the area of the bottom of the box is ... 3456 / 6 = 576 (x + 12) [(576 / x) + 12] = 1500 x is one dimension, 576/x is the other

*February 6, 2017*

**Physics**

800 N * 20 m = 16000 J per second means 16 kilowatts

*February 6, 2017*

**Math**

h(g(x)) = 9 - (x + 3)^2 ... = -x^2 - 6x the max is on the axis of symmetry ... x = -b / 2a = 6 / -2 = -3 plug in -3 to find the maximum

*February 6, 2017*

**science**

v = mass/density = 2.4 kg / 2.70 g/cm^3 2.4 is only 2 sig fig

*February 6, 2017*

**Math**

let x be the edge length of the corner squares the volume of the box is ... v = x (12 - 2x)^2 ... v = 144 x - 48 x^2 + 4 x^3 the 1st derivative will show the maxima/minima plug in the values to find the volume

*February 6, 2017*

**Physics**

the difference in densities gives you the "lift mass" per m^3 v = 800 kg / (1.25 kg/m^3 - 0.18 kg/m^3)

*February 6, 2017*

**Physics**

the metric unit of pressure is the Pascal (Pa) ... one Newton of force over one square meter a cubic meter of water has a mass of a thousand kg (a metric ton) ... it exerts a force of 9.81 kN stacked 100 high, the pressure at the bottom is ... 981 kPa

*February 6, 2017*

**Algebra**

the vertex is on the axis of symmetry x = -b / (2 a) = -6 / (2 * -1) = 3 plug 3 into the function to find the y-coordinate

*February 6, 2017*

**physics**

a straw works because when you lower the pressure on one end (by sucking), atmospheric pressure pushes the liquid from the other end the airtight cork prevents the atmospheric pressure from pushing on the liquid, so it won't go up the straw

*February 6, 2017*

**physics**

a cubic meter of water is a metric ton ... 1000 kg .4 m^3 / 24 m^2

*February 6, 2017*

**Intermediate Algebra**

c + h = 150 ... 325 c + 325 h = 325 * 150 325 c + 525 h = 445 * 150 subtract equations to eliminate c ... then substitute back to find h

*February 5, 2017*

**Math**

0 = x^2 - 2x + 15 x = [2 ± ?(4 - 60)] / 2 x = 1 ± i?14

*February 5, 2017*

**physics**

v is squared, doubling the uncertainty the value is then divided by y, which adds its uncertainty (2 * 3.34%) + 5.00%

*February 5, 2017*

**physics**

v is sq

*February 5, 2017*

**physics**

gas is correct

*February 5, 2017*

**physics**

the ke at the bottom equals the pe at the top both measured in Joules

*February 5, 2017*

**physics**

e = m g h = 7.2 * 9.8 * 1.2 (Joules)

*February 5, 2017*

**math**

worst case ... he takes out 5 ya and 7 gp the 13th fruit will fill the requirement

*February 5, 2017*

**maths**

find the average area of the top and bottom multiply by the height ... this is the volume in cm^3 divide by 1000 to find litres

*February 5, 2017*

**Algebra**

savings is dependent on weeks (98 - 65) / (6 - 3) = $11 / wk

*February 5, 2017*

**Alg/Trig**

0 = -16 t^2 + 112 t factoring ... 0 = -16 t (t - 7) 0 = -16 t ... t = 0 (launch) 0 = t - 7 ... t = 7 (return)

*February 5, 2017*

**9th grade physical science**

the density

*February 5, 2017*

**Science**

as the stone travels upward, its kinetic energy becomes potential energy the potential at the top is equal to the kinetic at the bottom ... e = 1/2 m v^2 = m g h ... h = ?[v^2 / (2 g)]

*February 5, 2017*

**Pre-Calculus**

?[389^2 + (389 + 50)^2]

*February 5, 2017*

**science**

h = -1/2 g t^2 + 7 t + 55 h is zero when the bottle hits the ground 0 = -4.9 t^2 + 7 t + 55 you want the positive solution

*February 5, 2017*

**Algebra2**

30 * (54/42)^2 * (26/85)

*February 4, 2017*

**physics**

do they start timing at a crest? there are 19 wavelengths between 20 crests

*February 4, 2017*

**Chemistry**

K.E. = 1/2 m v^2 look up the mass of the electron (in kg), and solve for v

*February 4, 2017*

**Math**

f = t - 20 j = 2f = 2t - 40 p = 3j = 6t - 120 9t - 180 = 340 solve for t, then substitute back

*February 3, 2017*

**Science**

Elodea uses photosynthesis to convert carbon dioxide and water into oxygen and carbohydrate the most bubbles should be in the carbon dioxide enhanced sample the degassed sample should have no bubbles the oxygen enhanced sample should be somewhere in between

*February 3, 2017*

**math**

b = 20000 (1 + .07)^6

*February 3, 2017*