Monday

February 8, 2016
Total # Posts: 37,472

**Algebra**

2(7.5+x) >= 58 Surely there is a maximum though, eh?
*January 14, 2016*

**math**

(5/8)x = (3/8)x + 50 5x = 3x + 400 2x = 400 x = 200
*January 14, 2016*

**Math**

The altitude AR is perpendicular to the line BC. BC has slope 1, so AR has slope -1 The line through A(-3,2) with slope 1 is y-2 = -(x+3) x+y = -1
*January 14, 2016*

**Math OOPS My Bad**

Sorry I yelled. I missed the word "altitude" in there. I'll solve it in my next post.
*January 14, 2016*

**Math**

LISTEN UP! You ask us about the line AR, but you still haven't told us anything about point R!!! Where is it, in relation to ABC?
*January 14, 2016*

**Math**

we are only interested in the 4th graders. 7/10 = 70%
*January 14, 2016*

**math - eh?**

You want to try that again in English?
*January 14, 2016*

**Math**

well, 40 dm = 4.0m so, what do you think?
*January 14, 2016*

**Math**

since the angles at the puddle are equal, we have similar triangles, so the height h of the flagpole in feet is given by h/20 = (31/6)/8
*January 14, 2016*

**science**

clearly, since CO2 is a gas at room temperature, and water is a liquid, water has the higher boiling point. As to why, google your question, and you will find many discussion on the topic, taking into account several properties of the two compounds.
*January 14, 2016*

**Pre Algebra**

by definition (√a)^2 = a or, using the rules of exponents, √a = a^(1/2) so, (√a)^2 = (a^(1/2))^2 = a^(2 * 1/2) = a^1 = a
*January 14, 2016*

**Math**

In any isosceles triangle, the perimeter is the base plus 2 times one of the legs. Clearly the base here is 8. No idea where R is. X = (A+B)/2 = (1,6) Z = (B+C)/2 = (7/2,3) XZ in two-point form is y-6 = (-6/5)(x-1) Now just rearrange that into standard form. across y = -5: (x,...
*January 14, 2016*

**MATH HELP ASAP**

23.8-5.8 = 18 so, -6q = 18 q = -3 Just take it step by step. Get all the variable stuff on one side, then it's easy.
*January 14, 2016*

**Math**

seems true, but the language is poorly worded.
*January 14, 2016*

**Math**

why all the words? That's why we have math symbols (4^-3)(3^4)(4^2) / (3^5)(4^-2) Add powers in product, subtract powers in divisors: 4^(-3+2-(-2)) * 3^(4-5) 4^3 * 3^-1 4^3/3 I suspect a typo in the problem or in the answers. Of course, you need to check my arithmetic, I ...
*January 14, 2016*

**maths**

50*30 = 1500 54*26 = 1404
*January 14, 2016*

**computer**

can't spell
*January 14, 2016*

**math**

To construct a 4x4 magic square, list all the values, left to right, top-to-bottom. Now, leaving the diagonals in place, reverse the order of the other numbers, going right-to-left, bottom-to-top. Google magic squares. Squares of odd order are easy to construct, following a ...
*January 14, 2016*

**Math**

Don't worry about finding negative square roots. Every square root has a corresponding negative root. That is because if the positive root is n, Then n^2 is its square. (-n)(-n) = n^2 also gives the same value when squared. So if you find that 4^2= 16, (-4)^2 is also 16. ...
*January 14, 2016*

**Geometry**

use the point-slope form of the line: y-0 = 2(x-4) or y = 2x-8 Now, check the choices and see which one works when used in that equation.
*January 14, 2016*

**Geometry**

a-b < c < a+b Looks like A to me. D is wrong, because if c=9 or 25, the triangle is just a flat line. Try drawing it.
*January 14, 2016*

**MATH HELP FAST AND I MEAN NOW I NEED THE ANSWER!!!**

Is that Fahrenheit or Celcius degrees?
*January 14, 2016*

**Calculus AB**

v = πr^2h dv = 2πrh dr + πr^2 dh h is assumed exact, so dh=0. dv = 2πrh dr dr = 0.2, so dv = 2π(4)(12)(.2) = 19.2π and that's ± Your estimate assumes that the height was also measured with an error. The problem does not say that. If ...
*January 14, 2016*

**Math**

it works just like a rectangle: 2(12+x) = 42
*January 14, 2016*

**Geometry**

Yes, it certainly is confusing.
*January 14, 2016*

**math**

well, just expand and equate coefficients: 2x^3 +7x^2-x-6 = Ax^3+(AB-A+1)x^2+(B+3-AB)x+(-B-C) So, you have A = 2 AB-A+1 = 7 B+3-AB = -1 -B-C = -6 A=2, so you have 2B-2+1=7, so B=4 That better work with B+3-AB = -1 4+3-2*4 = -1 -- check -B-C = -6 -4-C = -6 C=2
*January 14, 2016*

**Homework for Math**

ax^2 + bx + c = 0 a(x^2 + b/a x) = -c x^2 + b/a x = -c/a x^2 + b/a x + (b/2a)^2 = (b/2a)^2 - c/a (x + b/2a)^2 = b^2/4a^2 - c/a (x + b/2a)^2 = (b^2-4ac)/4a^2 x + b/2a = ±√(b^2-4ac)/2a x = [-b±√(b^2-4ac)]/2a
*January 14, 2016*

**math**

just expand the right side and the equate coefficients of like powers. If the polynomials are identical, all the powers of x must have the same coefficients. You can see right off that the right side will have 2Ax^2+... So, 4 = 2A and A=2 and so on.
*January 14, 2016*

**Math**

take a look at the sum (a1-a2)+(a2-a3)+...+(a98-a99)+(a99-a100) Everything cancels out except a1 - a100
*January 14, 2016*

**Possessive form**

looks good to me.
*January 14, 2016*

**AAHOOOOGAAAHH! Homework Dump!**

You not gonna provide any effort at all?
*January 14, 2016*

**math**

no idea, but they add up to 90 degrees.
*January 13, 2016*

**Pre- Algebra**

sort of. Multiply each item's price by the quantity of that item. That gives the amount spent for that item. Then add up the products to get the total amount spent. 24.95x + 4.75x + 29.99*1 That can be simplified into 29.70x + 29.99
*January 13, 2016*

**Geometry**

ummm, that's the definition of a parallelogram.
*January 13, 2016*

**Math**

See http://www.jiskha.com/display.cgi?id=1452644352
*January 13, 2016*

**algebra 1**

since distance = speed * time, if the boat's speed is b and the stream's speed is s, 7(b+s) = 280 14(b-s) = 280 b+s = 40 b-s = 20 b=30, s=10
*January 13, 2016*

**Calculus AB**

How do you get g(2x)=8 at x=1? g(2) = 4 Anyway, take a peek here and I think it will become clear. Just be sure to include that final 2 for the g(2x) instead of g(x). http://www.calculus-help.com/6-table-derivatives/ scroll down to the end.
*January 13, 2016*

**Algebra**

google is your friend
*January 13, 2016*

**math**

since 24 is the LCM of 6 and 8, cut each piece into 3rds. Then there are 24 pieces, and each person gets 4.
*January 13, 2016*

**Math - typo**

somehow the √13 became √3, but I'm sure David can fix that, eh?
*January 13, 2016*

**Math**

because the ratio of the change in y to the change in x is constant. Draw any two right triangles whose diagonal is a section of the line, and they are similar, since the have common angles.
*January 13, 2016*

**Math Help!**

assuming you mean two 5's, then they add up, making 10N.
*January 13, 2016*

**Math**

h = 2f+3
*January 13, 2016*

**math - bogus**

Not only is your sentence incomplete, but you provide no information as to the scale of the map. try proofreading your posts...
*January 13, 2016*

**math**

Assuming that the present will actually fit within the box, then the empty space is the difference between the volumes: 2.5 * 2 * 1.5 - 3 = ?
*January 13, 2016*

**Math**

6*6*6*6 = 6^4
*January 13, 2016*

**Math**

if 100 is 35% of the price, then the original price is 100/.35 = $285.71 so, ...
*January 13, 2016*

**Math**

the depreciation factor is r, where r^6 = 2800/31000 = 0.090 The value after 3 years is thus 31000 * r^3 = 31000 * √.09 = 31000 * .3 = 9300
*January 13, 2016*

**Math**

There are 5! = 120 ways to arrange 5 subjects. Now, the 6th subject (which just happens to be one of the 5 as well) can be inserted in any place in the schedule. So, there are 6 places to insert it. The 6th subject can be any of the 5, so there are 5 ways to choose it. So, ...
*January 13, 2016*

**math**

come on, do some thinking. If a number is divisible by 5, it must end in 5 or 0. In this case, 5 must be the 3rd digit. That leaves 2,3,6,7,9 for the other two digits. So, there are 5 ways to pick the 1st digit. Once it has been picked, there are only 4 choices for the 2nd ...
*January 13, 2016*

**Algebra**

(a) no solutions. How can 4x-y be both -1 and -3? (b) many solutions: if you multiply the first equation by 2, you will see that both equations describe the same line. Google is your friend. Use it to get lots of examples of linear equations in problems. To solve by graphing, ...
*January 13, 2016*

**Math/Physics**

Draw a diagram. Review the definition of the cotangent. If the height is h, then h cot19° - h cot23.8° = 910
*January 13, 2016*

**Math**

what? eh? huh? Mark point T (the tee) Mark point H (the hole) Draw the line TH. Draw angle at T 21° from the line TH. Mark point (B) on that line roughly 3/5 as far from T as H is. Can you see the triangle?
*January 13, 2016*

**Geometry**

No idea, since you do not describe the figure.
*January 13, 2016*

**science help**

data is information. A is redundant. I'd say D.
*January 13, 2016*

**Math**

why can you not just say x/3 instead of the "over"? sheesh. -9p-17 = 10 -9p = 27 p = -3 x/3 - 10 = 12 x/3 = 22 x = 66 and so forth.
*January 13, 2016*

**Vector and scalar quantity**

3,5 - 4,3 = -0,8 so the resultant points to the left. I expect you can draw your own diagrams. Oh, wait -- maybe not, or you'd have seen the answer already...
*January 13, 2016*

**Math Correct Me!!**

The common multiple is 3, because 12*3 = 36 see http://www.phschool.com/iText/mgmath_course2/Ch05/05-04/PH_MSM2_ch05-04_Obj1.html and scroll down a bit. 4/5 = x/27 4*27 = 5x x = 108/5
*January 13, 2016*

**Algebra**

Try plotting the points. Note that (3,2) and (3,-9) form a vertical line of length 11 The point (2,-9) is one unit away, so you have a triangle with base 11 and height 1. Now, is that so hard?
*January 13, 2016*

**math**

.75x + 2 = .80x Now you can find x
*January 13, 2016*

**Maths**

After t hours, the distance d can be found by d^2 = 15t^2 + (5-10t)^2 2d dd/dt = 30t + 2(5-10t)(-10) 2d dd/dt = 230t-100 dd/dt = (230t-100)/(2d) since d is never zero, that means dd/dt=0 when t = 10/23 hours
*January 13, 2016*

**Mathematics, Vector, Physics**

come on. That's just 70 sin45° a wind from the southeast is blowing northwest
*January 13, 2016*

**Mathematics, Vector, Physics**

Let's see what I get h = 375.877i+136.808j w = -49.497i+49.497j so, v = 326.380i+186.305j = 375.810 @ 60.28° and those are headings, not bearings!
*January 13, 2016*

**Math**

Oops. that's 30θ = π
*January 13, 2016*

**Math**

s = rθ Plugging in your numbers, 60θ = π
*January 13, 2016*

**math**

I think you need to explain a bit more. Clearly the equation as written is false.
*January 13, 2016*

**math**

well, AB=15, so draw the triangle and it will be clear.
*January 13, 2016*

**Maths**

Do you mean r = -(1/2)^n?
*January 13, 2016*

**Algebra**

If their ages are x,y,z then we have z = y-4 y = 2z Clearly, Joe is 4 and Kyle is 8 so, ...
*January 13, 2016*

**Math**

9.96^2 = 99.2 in^2 24 ft^2 = 24*144 = 3456 in^2
*January 13, 2016*

**math**

If there is a common ratio, then you need (2x+4)/(6x+12) = (x-7)/(2x+4) x = 25 So, the common ratio is 54/162 = 1/3 Since |r| < 1, the sequence converges.
*January 12, 2016*

**algebra**

x^-2y = y/x^2 6z^-1 = 6/z If you want a single fraction, then that would be (yz+6x^2)/(x^2z)
*January 12, 2016*

**Calculus - Finally!**

1/2 log(u^2/(1-u^2)) 1/2 log(sin^2(x/2)/cos^2(x/2)) log(tan(x/2)) -log(cot(x/2)) -log((1+cosx)/sinx) -log(cscx+cotx)
*January 12, 2016*

**Calculus**

Well, I made a blunder, but you should have caught it. dx = 2/cos(x/2) du so, the integral becomes ∫ 1/2sin(x/2) * 1/cos(x/2) * 2/cos(x/2) du = ∫ 1/(u(1-u^2)) du = log(u) - (1/2)log(1-u^2) = (1/2)log((u^2/(1-u^2)) I feel that is headed somewhere we want. As usual, ...
*January 12, 2016*

**calculus**

dv/dt = 1.6t^3/√(0.2t^4+8100) Let u = 0.2t^4+8100 du = 0.8t^3 dt Now you have dv/dt = 2du/√u v(t) = 4√u + c = 4√(0.2t^4+8100) + c Now plug in your numbers to find c, and then find v(10).
*January 12, 2016*

**Math**

512 = 8^3 so the area is 6*8^2 Just to be precise, volume is not measured in cm^2.
*January 12, 2016*

**Math**

(n+2)^2 = 2n^2 - 1 You might think that it would be possible for n to be even, but since the right side must be odd, so must n^2 be odd, and thus any solutions you find will be odd.
*January 12, 2016*

**i need help**

that's one way.
*January 12, 2016*

**i need help**

d/12 = 24.5/7
*January 12, 2016*

**Algebra**

94 + x <= 110
*January 12, 2016*

**math help please**

since d = kf, d/f = k and is constant. So, you want d such that d/12 = 24.5/7
*January 12, 2016*

**Math**

the numbers are 1,5,9,... The nth white bead is bead number 4n-3
*January 12, 2016*

**math help**

10m = 1000 cm So, multiply the drawing dimensions by 1000.
*January 12, 2016*

**Calculus AB**

Maybe you have heard of Rolle's Theorem, a special case of the MVT.
*January 12, 2016*

**maths - incomplete**

depends on how much per ounce the 16-oz jar costs. Figure that out, subtract 5 cents, and then multiply that by 24 oz.
*January 12, 2016*

**Math**

which number has only two pairs of factors?
*January 12, 2016*

**Math**

#1. Nope. Add 7 to both sides #2. Nope. What is 5.5-4.5 again? #3. Nope. Subtract 12 from both sides #4. Nope. At least means not less than, right? Batting a big zero on this one.
*January 12, 2016*

**Algebra**

if the width is w, then the length is 200-w. (why?) the area is w(200-w). Can you take it from there?
*January 12, 2016*

**Math**

75 * 1.20 = 90
*January 12, 2016*

**Calculus**

800 @ 140° = <514,-613> 130 @ 27° = <59,116> So, you want <x,y> such that <x,y>+<59,116> = <514,-613> Once you have x and y, then convert back to speed and heading.
*January 12, 2016*

**maths**

it will float if its density is less than water's (1g/cm^3) so, figure your density and then answer the question.
*January 12, 2016*

**Math**

3x/3 = x so, ...
*January 12, 2016*

**math**

Since constants cannot intersect lines or parabolas in infinitely many points, and lines cannot intersect parabolas in more than two points, D is the only choice: the two expressions describe the same parabola.
*January 12, 2016*

**Geometry 1 question**

just use your distance formula. Or, the Pythagorean Theorem. Plot the points. The distance you want is just the hypotenuse of a right triangle with legs 8 and 3. So, it is √(8^2+3^2) Better study your material some more.
*January 12, 2016*

**MATH help**

B is exactly the opposite of true. The output depends on the input. Try C. Usually when making a table, you list the values of the independent variable, and then figure out the dependent values in column 2.
*January 12, 2016*

**Algebra help help!!!**

4^x-3^(x-1/2)=3^(x+1/2)-2^(2x-1) 4^x - 3^x/√3 = √3 3^x - 4^x/2 (3/2) 4^x = (√3+1/√3)3^x (3/2) 4^x = (4/√3) 3^x (4/3)^x = (8/√27) (4/3)^x = (4/3)^(3/2) x = 3/2
*January 12, 2016*

**PHYSICS**

there is no atom just free electrons which disperse or are attracted by some other charged particles
*January 12, 2016*

**Physics Component Method**

the components are (just as in polar coordinates): x = r cosθ y = r sinθ You have r and θ, so plug and chug.
*January 12, 2016*

**Shurley English**

true, but the words are preposition, noun, noun, conjunction, pronoun, verb, adjective, adjective, noun, preposition, noun.
*January 12, 2016*

**Algebra**

If there are x multiple-choice questions, then there are 15-x open ones. 4x + 12(15-x) = 100
*January 12, 2016*