Thursday
February 11, 2016

Posts by Steve

Total # Posts: 37,565

algebra
x+(66-x) = 3x+6
January 22, 2016

maths
if the roots are a,2a,b then a+2a+b = 7 2a^2b = -36 a*2a + ab + 2ab = 0 or, a(2a+3b) = 0 so, b = -2a/3 Solve those and you find 3,6,-2
January 22, 2016

pre calculus
The tires will turn (218*5280*12)/(25π) times There are 360 degrees per revolution ...
January 21, 2016

pre calculus
Draw a diagram. assuming the line runs along the bottom of the pool, The angle is x, where tan(x) = 9/√(25^2+30^2)
January 21, 2016

Algebra
b(x) = f + rx
January 21, 2016

solid mensuration
since the base is not square, the base angles on unequal sides cannot be the same. So, which side(s) are we talking about? Anyway, once you have decided on the side to pick, the height is s tan30 = s/√3 where s is the length of the base side adjacent to the sloping face.
January 21, 2016

Math
2/6 * 30
January 21, 2016

math
(100)(90)(80) - (100-4)(90-4)(80-4)
January 21, 2016

English
#4 is a prepositional phrase. Even though "to" is used for infinitives, "the library" is not a verb. #6 "source" is a noun #7 "us" cannot be any kind of nominative; it is in the objective case. So, what kind of object is it? #10 better ...
January 21, 2016

mathu
28 * w = 280
January 21, 2016

comparing decimals
well, it has to be a number between 2.80 and 3.40 There's only one of those among the choices.
January 21, 2016

Math
1000oz/2hr * 1c/16oz * 1hr/60min = (1000)/(2*16*60) c/min
January 21, 2016

math help
Nope. 3.66 is the largest of the values, but when using negative numbers, larger values are less than smaller ones. Plot them on the number line. The farther to the left you go, the less the number.
January 21, 2016

history help
google is your friend. Much discussion provided.
January 21, 2016

Science
I think you'd better reconsider your answer. Immunity is internal to the body. Which of the choices is external?
January 21, 2016

physics 1
(1/3)(13ac*43560ft^2/ac)(480ft)(.3048m/ft)^3 = 2.5656*10^6 m^3
January 21, 2016

physics 1
volume in ft^3: (80ft)(22ft)(8ft) Since 1ft = .3048m, volume in m^3 = (80ft*.3048m/ft)... = (80)(22)(8) (.3048)^3 m^3 now do the same with (100cm/m)^3
January 21, 2016

science
find some insulating matter.
January 21, 2016

math i need help
I dunno -- it sure looks like Alg1 to me...
January 21, 2016

English
Seems to me that church bells would become bells of the church. I've only run across long form possessives in Spanish, and the rules are somewhat different there.
January 21, 2016

Calculus
well, you want |tan(x)| = 1 tanx = 1 or -1 you know that tan π/4 = 1 so use that as your reference angle. The rest is easy. . . . right?
January 21, 2016

Algebra
all you have to do is rearrange terms so that the equation is in the form Ax + By = C Can you not figure out how to get the x stuff on the left side?
January 21, 2016

Algebra
1st step: clear the fraction by multiplying by 5: 5y = -2x-3 Now you finish it up.
January 21, 2016

math
the first two walls are 2 tiles wide The third wall is 1 tile wide. Total length is 5+9+2 = 16 ft = 8 tiles long So, if you can use the cut pieces of tile, that's 8x5 = 40 tiles Those are some big tiles!
January 21, 2016

History
or, just click on your name above, and you will get a list of all your questions.
January 21, 2016

Math
good job.
January 21, 2016

Math
1-4 ok #5 you have chosen 48% of 30, not the correct value. Do it like #1.
January 21, 2016

Math
or, picking up at (7a^2 - 7)/(a-1) = 84 7(a-1)(a+1) / (a-1) = 84 7(a+1) = 84 a+1 = 12 a = 11
January 21, 2016

MATHS
1/t = 1/3 - 1/5 now solve for t.
January 21, 2016

math
regardless of the total mass, the proportion is clearly 16:2
January 21, 2016

math
area = 2(24*27+24*10+27*10) the area does not double: original area: 2(xy+xz+yz) new area: 2(2x*2y+2xz+2yz)
January 21, 2016

math
all: 2*2.5^2 + 4*2.5*3.5 to exclude the bottom, subtract 2.5^2 from that total. now compare in whatever way you want.
January 21, 2016

math
if the squares have sides x and y, then 4x+4y = 100 or, x+y=25 x^2+y^2 = 425 My vast experience tells me instantly that 425 = 400 + 25 = 20^2+5^2
January 21, 2016

Math
since time = distance/speed, if the bus's speed is x, then 40/x + 40/(x+20) = 9/10 Now just find x, and x+20
January 20, 2016

Calculus
9cos2x - 27cosx + 18 = 0 9(2cos^2x-1)-27cosx+18 = 0 18cos^2x - 27cosx + 9 = 0 2cos^2x - 3cosx + 1 = 0 (2cosx-1)(cosx-1) = 0 cosx = 1/2 or 1 Take it from there.
January 20, 2016

math
use the law of cosines to get BC, knowing that angle a is 130 degrees. then use the law of sines to get angle B, and then you can figure the bearing of C.
January 20, 2016

graphing linear non proportional relationships usi
visit http://www.wolframalpha.com/input/?i=-0.04^x%2B+12
January 20, 2016

Math
volume of tank is v = π(15^2)(50) depth of water is d = v/(20*40)
January 20, 2016

Pre Algebra
2d = 8r d = 4r now you can play around
January 20, 2016

Pre-calculus
well, you know that the cross-section is x^2 and the length is y, so v = x^2y but, you also know that 4x+y = 300 now you can eliminate y.
January 20, 2016

math
nope. There will be 1/125 of a bag in each snackbag, but that was not the question. 1/25 of the nuts will be in each snackbag, regardless of the original quantity. Unless you garbled the question ...
January 20, 2016

mathematics
is there a question in there somewhere? try typing the expressions in the box at wolframalpha.com and see what you get.
January 20, 2016

Pre-Calc
correct
January 20, 2016

Math
you are going to need a calculator of some kind, unless you want to evaluate 500(1.042^7) - 500 by hand By the way, D is the amount in the account, but it is not the answer to the question.
January 20, 2016

Math
I can factor expressions, but not problems. You want two factors of 42 that differ by 1, so that when you subtract (because of the -42) you have 1 left over: (x+7)(x-6) = 0 Then, the other is (2x+3)(x+2) = 0
January 20, 2016

Math
divide 70 into 7 equal parts, x. Then 4x+3x = 70
January 20, 2016

Maths
subtract and you get e = 2f-13 Now substitute that into either equation to get f. Then you can evaluate e.
January 20, 2016

Math
nope. D is the total amount in the account, but is not the correct answer.
January 20, 2016

Algebra
x = 2y-30, so 2y-30 + y = 90 now you can find y, and then x.
January 20, 2016

math
a slope of 1.25 means that y changes 1.25 as fast as x. The base of the triangle is 7 units long, so the height is 7*1.25 = 8.75 units. (2,2)+(7,8.75) = (9,10.75)
January 20, 2016

Precalculus
well, you know that the vertical distance from (6,1) to y=5 is 4. So, using a 3,4,5 triangle, the two points are 3 horizontal units away from (6,5), at (3,5) and (9,5) If you use your distance formula, you can verify that both of these points are 5 units away from (6,1).
January 20, 2016

maths and science
note that 2=8/4 (8/4)/(125/4) = (8/125) = (2/5)^3 Looks to me like r = 2/5 and there are 4 terms: 125/4, 25/2, 5, 2 the sum is 203/4
January 20, 2016

math
It will take n years, where 1000*.15*n = 100 similarly for the other part.
January 20, 2016

Math
google is your friend. look up scaling for many examples.
January 20, 2016

Math
surely you can figure out that the answer is 13+13+13+13+13+13 = 13*6 = 78
January 20, 2016

math
just write what they give you: xy = 288 (x-1)(y+1) = xy-3 Now just solve for x and y, and you have 16 by 18. Or, just list the factors of 288 and 285: 9x32, 12x24, 16x18 3x95, 5x57, 15x19 and it's easy to see which pairs work.
January 20, 2016

Math
If she ran x miles on 5 of the days, then we have 5x+12 = 42
January 20, 2016

math
cost is 15x, so 20(x-6) = 15x+480
January 20, 2016

Physical science
2*(10cm)^3 * 11.35g/cm^3 * 1kg/1000g = ? kg
January 20, 2016

Physics
2dm is length, not volume. 2dm^3 = 2(10cm)^3 = 2000cm^3 Now use that to get the mass in g, then convert that to kg.
January 20, 2016

Math
They each started out with x. So, together they had 2x stickers. x+72 = 3(x-72) x+72 = 3x-216 2x = 288
January 20, 2016

science
see https://en.wikipedia.org/wiki/List_of_moments_of_inertia
January 20, 2016

Math
we already went through this. There are 2*2=4 hundredths, so you cannot have 3 times that many ones, since the maximum digit is 9.
January 20, 2016

Mathematics
2x+2y-10 = 150 x+y = 80 area = xy = x(80-x) Just find the vertex of that parabola for maximum area.
January 20, 2016

math
well, 1512 has a number of factors. So, if you pick 21 and 72, then dividing by 2 and adding gives you 46.5 If you pick 84 and 18, then the sum is 51. Maybe you meant the new product, not sum. I'm sure you can figure out what happens then.
January 20, 2016

math
well, the primes are 23 and 29 Now 23+29=52, not both digits are even. Hmmm. Did you mean two-digit even number?
January 20, 2016

Pre-Calc
yeah - so? the expression still evaluates to 1.
January 19, 2016

Pre-Calc - My Bad
sinAcosB + cosAsinB = x*x + √(1-x^2)√(1-x^2) = x^2 + 1-x^2 = 1 of course- since if you draw the triangle, you are taking the sine of two angles which add to 90°
January 19, 2016

Pre-Calc
sin(arcsin(x)) = x cos(arcsin(x)) = √(1-x^2) so, if A = arcsinx B = arccosx ain(A+B) = sinAcosB + cosAsinB = x√(1-x^2) + √(1-x^2)*x = 2x√(1-x^2)
January 19, 2016

Math
profit of $13 per lawn. so, it takes 100 lawns to pay off the $1300. You are correct.
January 19, 2016

math geometry
Without either a diagram or a description, it's impossible to answer these questions. The parallel lines indicate to me that there are probably some alternate interior/exterior angles adjacent angles alternate angles are equal adjacent angles add to 180 I expect you can ...
January 19, 2016

Math
"at least" means >= care to change your answer?
January 19, 2016

Calculus
for y=e^x, the slope of the normal at x=a is -e^-a for y=lnx, the slope of the normal at x=b is -b. So, we want to find a and b such that the normals through (a,e^a) and (b,lnb) are the same line. That is, y-e^a = -e^-a(x-a) and y-lnb = -b(x-b) eliminating y, we then want -e^-...
January 19, 2016

English
In " Tokyo" Ryo and Tsuruishi have all of the following in common except they both have children they both been married they are familiar with Siberia they are both rebuilding their lives My answer is a
January 19, 2016

Calculus
I think you are missing come values. For linear, figure the constant slope. For exponential, divide two known values to get a power of the growth factor. See your previous post for an example.
January 19, 2016

Calculus - typo?
a^1 = a If you meant f(t) = Qoa^t = Qo(1+r)^t then clearly a = 1+r Qo(1+r)^4 = 72.2 Qo(a+r)^10 = 176.7 Now divide and you have (1+r)^6 = 2.447 Now finding r is easy. After that, you can find Qo.
January 19, 2016

Calculus
Let V = ∫sin^2x dx Since cos^2x is a mirror image of sin^2x, ∫cos^2x dx = V Now, since sin^2x+cos^2x = 1, 2V = ∫[0,π/2] 1 dx = π/2 V = π/4 check: sin^2x = (1-cos2x)/2 ∫sin^2x dx = ∫(1-cos2x)/2 dx = 1/2 (x - 1/2 sin2x) [0,π/2...
January 19, 2016

Math
Awesome thank for the help 😀✌
January 19, 2016

Math
2 years ago my mother was 4 times my age then. In 18 years I will be half my mothers new age. How old am I now? I am so stuck 2 years ago Sx4-M (S+18)=(M+18)/2 Now what do I do
January 19, 2016

please show how to set up this problem
If Jenny gave x dollars, then we have .35*40 + (3/8)*40 + x = 40 14 + 15 + x = 40 x = 11 With word problems, just start writing the facts in symbols. You will end up with equation(s) to solve.
January 19, 2016

math - missing data
you left out the drawing size
January 19, 2016

Calculus
Assuming you mean x = 2e^t cos(t) y = 2e^2 sin(t) you know that x=cos(t) y=sin(t) is a circle, So, this is just a spiral, of radius 2e^t for angle t. http://www.wolframalpha.com/input/?i=x+%3D+2e^t+cos%28t%29%2C+y+%3D+2e^t+sin%28t%29+for+0%3C%3Dt%3C%3Dpi Now, the arc length is...
January 19, 2016

Math
Nope. Check your decimal point.
January 19, 2016

fraction maths
in one hour, the taps can fill 1/9 + 1/12 = 7/36 of the tank. So, in 3 hours, they fill 3 times that much: 3*7/36 = 7/12
January 19, 2016

math
if the chords have the same length, they are the same distance from the center. So, x^2 = 4x x = 4 or 0 So, they are 16 units from the center. Or, they are both diameters, passing through the center.
January 19, 2016

Math
sorry - no figures available here. Surely you must have some ideas on this massive homework dump!
January 19, 2016

Math
20 marbles, 1 blue So, P(blue,tails) = 1/20 * 1/2 = 1/40
January 19, 2016

Math
rotate clockwise from the +x axis. Since it's less than a quarter circle, it's in QIV.
January 19, 2016

Algebra
No idea whether the given inequality is correct, but if you're looking for an x which satisfies it, you just have to add 2 everywhere: 5 < x-2 < 11 7 < x < 13
January 19, 2016

geometry
216 = 6^3 = 6^2 * 6, so √216 = 6√6 3√216 = 18√6
January 19, 2016

Math
radius of circle is 2000+6400 = 8400 km. But that does not matter when all we want is the angular velocity. ω = (2πrad)/(3hr) = (2π/3) rad/hr
January 19, 2016

Trig
let's stick with yards. The distance between the goal posts is 6.5 yards. So, since arc length s = rθ, we want θ such that 50θ = 6.5 θ = 0.13 radians = 7.45° But, he can only deviate by 1/2 that, or 3.72° Plug in r=20 for the other part. ...
January 19, 2016

math
Pour milk back and forth so the 3 containers hold the amounts shown: 0 0 10 3 0 7 3 7 0 0 7 3 3 4 3 0 4 6 3 1 6 0 1 9 1 0 9 1 7 2 3 5 2
January 19, 2016

calculus
hmmm. we want the line passing through (a,b) and (c,d) such that c^2 - d^2/3 = 1 b^2 = 8a (b-d)/(a-c) = 4/b (b-d)/(a-c) = 3c/d Due to symmetry, there will be two tangent lines, but one solution is (a,b) = (1/2,2) (c,d) = (-2,-3) See the graphs at http://www.wolframalpha.com/...
January 19, 2016

Maths
Looks like a 5-digit number with two decimal places: abc.de abc.2e abc.24 1bc.24 12c.24 12?.24 There can be a max of 9 ones, but 3*4=12.
January 19, 2016

chemistry
you are reducing the concentration by a factor of 9/21 = 3/7. So, that means you must increase the volume by a factor of 7/3. So, just add 4/3 of the original volume, using the diluting agent. As an example, if you have 3mL of 21% solution, adding 4mL of water will give you ...
January 19, 2016

Math
Thanks for stopping by, bob... If the number of $25 increases is x, then U = 90-x R = 1300+25x So, that means x = 90-U x = (R-1300)/25 Equate the two expressions and you have 90-U = (R-1300)/25 U = 90-(R-1300)/25 or U = 142 - R/25
January 19, 2016

CSAB/Advance Algebra
start writing the facts: p+n+d = 65 n = 2p-4 d = n+13 For elimination, standardize the lines: p+n+d = 65 -2p+n = -4 -n+d = 13 Now visit http://www.gregthatcher.com/Mathematics/GaussJordan.aspx and enter your coefficients, and watch the details emerge.
January 19, 2016

Algebra 2
A handy synthetic division calculator can be found here: http://www.mathportal.org/calculators/polynomials-solvers/synthetic-division-calculator.php You will have to adjust your divisor to account for the leading 3.
January 19, 2016

College Algebra
original dimensions: x and x+5 (x-2)(x+5-2)(1) = 644 Now just solve for x.
January 19, 2016

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