Thursday

February 11, 2016
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*