how do you do this problem?

Question

5x(-x+ 7) = -13

Answer 1

just do it...........

Answer 2

x = 7.35357
or
x = -.35357

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It's gonna be difficult to write the problem out here, but I'll try.

One thing to remember, once you get zero on the right hand side, you can multiply each side by -1. That will make it easier to work with the left side, which then will be
5x² -35x -13 instead of -5x² +35x +13

That's much easier than having the -5x² on the left.

So once you have
5x² -35x -13
on the left, it's easier to work the problem.
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x = 35 (plus or minus) sq root of (-35)² -4.5 (-13)
OVER 2.5


= 35 ±· √1485
OVER 10

= 3.5±·3.85357

= 7.35357 (or) -.35357

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Proof:
If x = 7.35357

-5 (7.35357)² + 35(7.35357) + 13 =

-270.3750 + 257.3730 + 13 = 0

==================

Proof:
If x = -.35357

-5 (-.35357) +35 (-.35357) + 13 =

-.62516 - 12.37495 + 13 = 0

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You have to look really close, because it's hard to see the decimals and the minus signs. It's also hard to see the little squared sign, and the plus/minus sign is so small, it kinda runs together.

I'm sleepy, so I hope I copied it right. I hope I didn't leave out any steps when I wrote it here.

I need some sleep!

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Answer 3

The easiest way to solve for x in this instance is to distribute the 5x. So you are left with -5x^2 + 35x = -13. To solve a quadratic you then need to get everything on one side of the equation, so you add 13 to both sides leaving you with -5x^2+35x+13. Because you have a -5 in front of your squared term the easiest way to solve this is the quadratic formula.

Answer 4

Distribute the 5x and you get:
-5x^2 + 35x = -13

Add 13 on both sides:
-5x^2 + 35x + 13 = 0

You can't factor this so use the quadratic equation to solve it.

Answer 5

solve -5x^2+35x=-13...factor this out which will be 5x(-x+7)=-13. Then continue solving it (i dont have pen and paper with me now, sorry)