Best answer gets 10 points!?

Question

Factor
2xsquared-316x-15840

hey, i had to do a lot just to get to this but iam having trouble factoring it...

ohhh! Thank you so much thermo! iam not very good at teaching math to myself. thanks again!

Answer 1

Thermo and a few others got this right. The answer is

2(x - 198)(x + 40)

but most used the quadratic formula to do it. Thermo didn't; he factored 2x^2 - 316x - 15840 = 2(x^2 - 158x - 7920). But he didn't explain how he did it.

If you don't use the quadratic formula (or complete the square, which is the same thing), then you have to do -- which I think is what this question is all about.

We have to get two numbers whose product is 7920, and whose difference is 158.

To do that, break down the 7920. Divide out 20: 7920 = 20 x 396. Since 396 - 20 = 376, the spread is too big.

Now divide out a 4: 7920 = 80 x 99. Here, the difference is 99 - 80 = 19. That spread is too small.

The only thing left is 7920 = 40 x 198. That one works: 198 - 40 = 158.

So our answer is 2(x - 198)(x + 40).

That's how to do it rather than by using other methods.

Answer 2

2xsquared-316x-15840
=2x^2 - 316x - 15840

=2(x^2 - 158x - 7920).

Using the pythagoream thereom:
x = (-(-158) ± sqrt((-158)^2 - 4(1)(-7920)))/(2(1))
x = (158 ± sqrt(24964 + 31680))/2
x = (158 ± sqrt(56644))/2
x = (158 ± 238)/2
x = (396/2) or (-80/2)
x = 198 or -40

so this will factor to ,
2(x - 198)(x + 40)

Answer 3

2^2 - 316x - 15840

2 is a common factor for all these, so you'd factor out the 2.

This would then read:

2 (x^2 - 158x - 7920)

Answer 4

2x^2 - 316x - 15840

Assuming you are correct at getting to this point.

2(x^2 - 158x - 7920)

using the pythagoream thereom

x = (-b ± sqrt(b^2 - 4ac))/(2a)

x = (-(-158) ± sqrt((-158)^2 - 4(1)(-7920)))/(2(1))
x = (158 ± sqrt(24964 + 31680))/2
x = (158 ± sqrt(56644))/2
x = (158 ± 238)/2
x = (396/2) or (-80/2)
x = 198 or -40

so this would factor to 2(x - 198)(x + 40)

Answer 5

2xsquared-316x-15840 =
2(x^2 -158x - 7920) =
2(x - 198)(x + 40)

The trick: solve x^2 -158x - 7920 = 0

Th

Answer 6

2x^2-316x-15840
2(x^2-158x-7920)
2(x-190)(x+48)
splitting 158 so that the sum is -158
and the product-7920

Answer 7

It's a quadratic equation. Get out your beginner Algebra book and look it up. Study the example and you will be able to solve the problem. I could give you the answer, but it wouldn't help you solve these problems in the future. Good luck.

Answer 8

2xSq-316x-15840=0

Solve for X

Answer 9

The best answer always gets 10 points. And do your own homework.

Answer 10

2(x+44)(x-316)