Sunday

September 25, 2016
Total # Posts: 44,023

**physics**

If you have two vectors u and v, resultant is w = u+v equilibrant is w such that u+v+w = 0. That is, w = -(u+v)

*September 1, 2016*

**Maths**

let's call the roots a and b, just for ease of typing. f(x) = x^2-6x+k recall the sum and product of the roots: a+b = 6 ab = k Now, we have a^2 + b^2 = 40 but, a^2 + b^2 = (a+b)^2 - 2ab So, 36 - 2k = 40

*September 1, 2016*

**Math question for Steve**

yes. just figure the calls each day and keep adding them up. The table looked pretty clear to me. When the total exceeds 300, that's the day the 300th call was received.

*September 1, 2016*

**Math**

the slopes must be the same, so (8-1)/(-2-a) = (1-5)/(a+2-12) -7/(a+2) = -4/(a-10) 7(a-10) = 4(a+2) 7a-70 = 4a+8 3a = 78 a = 26

*September 1, 2016*

**Math problem soving**

Huh? Surely you can see that on day 6 the 300th call came in.

*August 31, 2016*

**Differentiation**

Rats. How about y x^(y-1) y' + lnx x^y + x y^(x-1) y' + lny y^x = 0 (y x^(y-1) + x y^(x-1))y' = -lnx x^y - lny y^x Note that x^(y-1) = x^y/x, so (y/x x^y + x/y y^x)y' = -lnx x^y - lny y^x ...

*August 31, 2016*

**Differentiation**

To differentiate u^v, where u and v are functions of x, use a combination of the easy formulas you already know: y = u^n y' = n u^(n-1) u' y = a^v y' = lna a^v v' x^y + y^x = 1 x^(y-1) y' + lnx x^y + y^(x-1) y' + lny y^x = 0 (x^(y-1) + y^(x-1))y'...

*August 31, 2016*

**Math**

The receiver is 10 yd downfield and 53 1/3 - 25 - 5 = 23 1/3 yds to the right. So, the distance is clearly √(10^2 + (70/3)^2) yds QB: (25,25) Rcvr: (35,48 1/3) So, take their averages to find the midpoint.

*August 31, 2016*

**Precalculus**

V(t) = 2600 - 145(t-13)

*August 31, 2016*

**9th grade algebra**

don't be scared by that x. It's juts a denominator. To get rid of it, multiply both sides by x. Now, to find x when h = -2, just do what you did: 12/x = -2 now just multiply by x: 12 = -2x x = -6

*August 31, 2016*

**Math**

x + 2(x+2) = x+4 + 20 Now just solve for x, the smallest

*August 31, 2016*

**Math**

(d/7) weeks, so (d/7)/4 = d/28 months

*August 31, 2016*

**math**

how do you drop by -5.7° Maybe you mean either it dropped by 5.7° or, it changed by -5.7° In that case, after 3.5 hours, the change is clearly -5.7 * 3.5° So, add that to the starting 23°, and what do you get?

*August 31, 2016*

**Math**

Or, it occurs to me that maybe you have garbled the question, and it should read $75 per month plus $0.30 per minute after the first thousand minutes In that case, it's just y = 75.00 for 0 <= x <= 1000 y = 75.00 + 0.30(x-1000) for x > 1000

*August 31, 2016*

**Math**

there is a flat fee of 75.00, so start with that: y = 75.00 Now, add .30 for each minute. For x minutes, that is .30x, so y = 75.00 + 0.30x No information is given on what happens after the first 1000 minutes, so all we can do is restrict the domain to what we know: y = 75.00...

*August 31, 2016*

**Pre-Calulus**

15000/15 - 15000/18 = 166.67 or, since the old car used 1000 gallons, the new car, with 20% (6/5) better mileage uses 5/6 as much gas, saving 1/6 of 1000 = 166.67 gallons.

*August 31, 2016*

**Algebra**

yes, just as with normal fractions 2/3 + 4/7 has an lcd of 4*7 3/4 + 1/6 has an lcd of 12 instead of 24, since 2 is a common factor of both 4 and 6. LCD(m,n) = mn/GCF(mn)

*August 31, 2016*

**Algebra**

x^2-9 = (x+3)(x-3) so that is the lcd 1/(x-3) + 1/(x+3) = 10/(x^2-9) multiply through by x^2-9 and you have (x+3) + (x-3) = 10 2x = 10 x = 5 For #2 if you mean 5/(2x) - 5/(3(x+5)) = (5/x) the lcd is 2x(3(x+5)) so 5(3(x+5) - 5(2x) = 5(2)(3(x+5)) 15x+75 - 10x = 30x+150 If I got ...

*August 31, 2016*

**algebra**

f^-1(9/x) = 9/x since f^-1(f(x)) = 9/(f(x)) = 9/(9/x) = x swap variables and solve for y: x = (2y+1)/(3-2y) x(3-2y) = 2y+1 3x-2xy = 2y+1 3x-1 = 2xy+2y 3x-1 = y(2x+2) y = (3x-1)/(2x+2)

*August 31, 2016*

**Algebra**

you only need an lcd if you are adding fractions with unlike denominators. Multiplication and division just work on the tops and bottoms separately.

*August 31, 2016*

**Algebra**

(5/8)/(-2/3) = (5/8)(-3/2) = -15/16 (x^-1+y^-1)/(x+y) = (1/x + 1/y)/(x+y) = ((x+y)/(xy))/(x+y) = 1/(xy)

*August 31, 2016*

**algebra**

s/3600

*August 31, 2016*

**Math**

The bill for x + 1/4 miles is .75 + .35x <= 7.40

*August 31, 2016*

**Math**

105 cannot be their least common factor, as it has its own smaller factors. Though I think the question has been garbled, since I cannot understand "two pairs of numbers of 105"

*August 31, 2016*

**biology**

surely you know what "complex" means and also the molecular level, as opposed to the more large-scale aspects. You know about molecules, right? So, given those ideas, and a little thought (and maybe some help from google) what do you think?

*August 31, 2016*

**linear algebra - can't grok**

your economy of typing (laziness?) makes your posting almost unintelligible. We don't mind helping you find the answers, but don't ask us to figure out the questions as well, ok? and what the heck is a signal lac?

*August 31, 2016*

**math**

24 students makes 12 pairs. There are 3 pairs to go. So, how many magnets is that?

*August 31, 2016*

**Math**

.30x = 90

*August 31, 2016*

**geometry**

how are the angles arranged? That is, what is the order of D,F,G,H around point E? Are there any right angles or straight angles in the picture?

*August 31, 2016*

**math**

yes

*August 31, 2016*

**Math**

7x1=7 7x2=14

*August 31, 2016*

**Biology **

Explain the following statement: "life is complex on a molecular level. How is your environment different from the biosphere?

*August 31, 2016*

**Math**

multiply all the powers by 4. 2^4 = 16

*August 31, 2016*

**Math**

two points cannot intersect B is also false, since the sign of the y-values are not both positive. This whole question appears bogus.

*August 31, 2016*

**Math**

If they lost x, then x + 2x+15 = 78

*August 31, 2016*

**Math**

(8/5) * 40

*August 31, 2016*

**Algebra 1**

5 more than x: x+5 5 more than (half Karen's salary): (k/2)+5 Your answer is half of (5 more than Karen's salary).

*August 31, 2016*

**Algebra 1**

correct

*August 31, 2016*

**Algebra help**

I like D!

*August 31, 2016*

**Algebra help**

oh, and speed is not measured in feet. Distance is measured in feet. Speed is measured in feet per second miles per hour or something else like that

*August 31, 2016*

**Algebra help**

I think so. speed depends on time and distance. None of the answers really is complete, but they all say something depends on something else. For a given distance, speed depends on the time it takes to travel that distance. So, if you want to determine Andy's speed, ...

*August 31, 2016*

**Algebra help**

speed = distance/time

*August 31, 2016*

**Math**

Draw a number line. You will see that -5 is to the right of -8. So, -5 > -8 and yes, -6 < |-8| = 8

*August 31, 2016*

**Mathematics**

yep

*August 31, 2016*

**Math**

Draw any convex polygon of n sides. From any vertex, there are n-1 other vertices to reach. But two of those are adjacent, so a joining line is just a side. That leaves n-3 other vertices. Joining to them will form diagonals.

*August 31, 2016*

**math work**

as long as we're using determinants, u•v×w = |9 -7 -3| |-6 1 -5| |2 8 -9|

*August 31, 2016*

**math work**

see related questions below

*August 31, 2016*

**Math**

maybe it's 7/12, since 1/3 + 1/4 = 7/12

*August 31, 2016*

**Science**

v^2 = 2as, so 25 = 10a a = 2.5 m/s^2 F = ma = 1.25N

*August 31, 2016*

**math**

9 1/4 - 15 2/6 = -(15 4/12 - 9 3/12) = -6 1/12

*August 31, 2016*

**math**

5 4/12 - 3/12 = 5 1/12

*August 31, 2016*

**math**

well, the chance that both are girls is 8/14 * 7/13

*August 31, 2016*

**Math**

rice: 11/18 tomatoes: 3/7 * 7/18 = 1/6 spinach: 1/4 * 2/9 = 1/18 1 - 11/18 - 3/18 - 1/18 = 3/18 so, 1/6 of the field is yams

*August 31, 2016*

**math**

88/2 = 44 44/2 = 22 22/2 = 11 2^3 * 11 = 88

*August 31, 2016*

**Math**

.20 * .65 * 25 = ?

*August 31, 2016*

**Pre-calculus**

see related questions below

*August 31, 2016*

**math**

why the decimals? We're practicing mixed numbers here 7 1/2 - 5 3/4 = 6 6/4 - 5 3/4 = 1 3/4

*August 31, 2016*

**math**

Take a look at the following article, and see what you can come up with: https://betterexplained.com/articles/navigate-a-grid-using-combinations-and-permutations/

*August 31, 2016*

**Geometry**

x^2+y^2+3x-8y+16=0 is the circle (x + 3/2)^2 + (y-4)^2 = 9/4 So, the center of the circle is at (-3/2,4) The distance to the line 4x+3y-12=0 is thus |4(-3/2) + 3(4) - 12|/√(4^2+3^2) = 6/5 So, the desired circle is (x + 3/2)^2 + (y-4)^2 = 36/25

*August 31, 2016*

**Geometry**

find the distance from the center of the circle to the line. Use that for the radius of the circle.

*August 31, 2016*

**maths**

9/12 = 75%

*August 31, 2016*

**maths**

Simon's distance: 6x Jade's distance: 11y 11*6 + 6x = 114

*August 31, 2016*

**algebra**

Start with the url below and fix your typos till you get one of your choices: http://www.wolframalpha.com/input/?i=solve+1%2F3x+%2B+3%2F4+y+-+2%2F3+z+%3D+-8,+x+%2B+1%2F2+y+-+1%2F3z+%3D+18,+1%2F6+x+-+1%2F8+y+-+z+%3D+-24

*August 31, 2016*

**math**

add the two equations and y drops out: 2x^2-22x = -48 x^2-11x+24 = 0 (x-3)(x-8) = 0 Now just find the y for each x.

*August 31, 2016*

**math**

If all you can do is multiply and divide, I don't see how it can be done. 5 and 7 are primes, and there is no way to cancel them as factors

*August 31, 2016*

**physic**

speed (m/s) = wavelength (m) * frequency (1/s) v = λf so, for a given frequency, the velocity is directly proportional to the wavelength. Get v in air, and then you can figure v in glass.

*August 31, 2016*

**physics**

T = kML

*August 31, 2016*

**math**

(a+b+c)^3 = a^3 + 3a^2b + 3a^2c + 3ab^2 + 6abc + 3ac^2 + b^3 + 3b^2c + 3bc^2 + c^3 so, (x^2+x+1)^3 expands as x^6 + 3x^5 + 3x^4 + 3x^4 + 6x^3 + 3x^2 + x^3 + 3x^2 + 3x + 1 which is what was above

*August 31, 2016*

**Algebra**

the first train is 40 miles ahead when the 2nd train starts. The 2nd train is going 10 mi/hr faster, so how long do you think it will take to cover the extra 40 miles?

*August 31, 2016*

**Math**

16/(26+19+21+26+32)

*August 31, 2016*

**Algebra**

google is your friend.

*August 31, 2016*

**Algebra 2**

all polynomials have a domain of all real numbers. Any straight line which is not a simple y = k horizontal line also has a range of all real numbers. To see this, just draw any line. It extends forever both left and right, and up and down. (unless ut is horizontal)

*August 31, 2016*

**Math**

71% of 519 is .71*519 = 368.49 (million) Not sure what you want to divide.\, nor what "work" you are referring to.

*August 30, 2016*

**math**

since BD bisects the angle, 5x+8 = 9x-14 x = 5.5 Now you can find ABC, which is ABD+BDC

*August 30, 2016*

**Math**

Since I have no idea of the diagram, it's hard to say. But I suspect you are dealing with angles on a transversal of parallel lines. Check into adjacent, alternate interior/exterior, etc.

*August 30, 2016*

**Geometry**

correct

*August 30, 2016*

**Algebra**

I get 3 x^1/4 (x^-3/2 + 2)

*August 30, 2016*

**Math**

In 3 years, an investment earns $108 simple interest at a rate of 3%. Find the principle. Thank You.

*August 30, 2016*

**Algebra**

Find the simple interest on an investment of $800 at a rate of 2.5% per year after 9 months.

*August 30, 2016*

**Math**

2050 * .02 = 41 care to change your answer?

*August 30, 2016*

**Math**

An investment of $2050 at a rate 2% interest earned in 164 in simple interest. Find the length of the time it was invested for My answer: 4 months

*August 30, 2016*

**Math**

remember your geometry, and theorems about angles formed by transversals of parallel lines, and their converses.

*August 30, 2016*

**Algebra**

3 g^-2 b^2 g^-2 = 1/g^2 so, the expressions is the same as 3b^2/g^2 1/g^-2 = 1/(1/g^2)) = g^2 Now we get into murky waters: (3/g^-2)h^3 = 3g^2h^3 -- not a choice 3/(g^-2h^3) = 3g^2/h^3 because that is the same as 3 * 1/g^-2 * 1/h^3 = 3g^2/h^3 don't be afraid to use ...

*August 30, 2016*

**Math**

clearly, 1,000,000 ------------ 10,000

*August 30, 2016*

**Math**

(3-2)*(10-5)*24

*August 30, 2016*

**Math**

3x + 2(3+x) - 1

*August 30, 2016*

**Math**

4/10 as many people means 10/4 as long to work. 5/2 * 6 = 15

*August 30, 2016*

**math homework**

5/n^5 (1^3 + 2^3 + ... + n^3)

*August 30, 2016*

**math homework help please?!!**

so, did you list the first 6 terms?

*August 30, 2016*

**math homework help please?!!**

substitute for y and you have x^2 + (16-x^2) = 128 Now just solve for x, and then get y.

*August 30, 2016*

**maths**

the area is |u×v| = |12i+14j+2k|

*August 30, 2016*

**math**

correct

*August 30, 2016*

**Math**

(1 + .085/365)^365 = 1.0887 or, 8.87%

*August 30, 2016*

**Math**

see related questions below

*August 30, 2016*

**Math**

correct

*August 30, 2016*

**Chemistry**

well, its density is 29.9/38.6 g/mL

*August 30, 2016*

**Math**

t seconds from the time of observation, the truck has gone 110km/hr * 1hr/3600s * 1000m/km * t s= 30.55t m cop car has accelerated at 44.44 m/s / 20s = 2.22 m/s^2 so its distance is 1.11 * 20^2 + (44.44(t-30)) so set them equal, and you find that the cop caught up after 64 ...

*August 30, 2016*

**Math**

Not quite. 1B ok 2D you lost the - sign 3C 4B ok 5C do not change the order of the numbers. That's Commutative. Plus you changed the 8 to -8.

*August 30, 2016*

**math homework help please?!!**

left limit: 13-1^2 = 12 right limit: 11-1 = 10 Looks like B to me Now, if it were 11+x, then the limit would be 1 from both sides. Note that f(1) is not defined

*August 30, 2016*

**math**

7x/8 = 21 7x = 168 x = 24 or, 7(x/8) = 21 x/8 = 3 x = 24 If you divided 21 by 8, you were just guessing.

*August 30, 2016*