Question

For what values of x is x2-36=5x true?

A. -9 and -4
B. -4 and 9
C. 4 and -9
D. 9 and 4

Answer 1

B. -4 and 9

Explanation:

move the 5x over and factor to get (x-9)(x+4)=0, set both of the expressions equal to zero, and solve, pretty much you just fator and flip the signs. Hope this helps!

Answer 2

B. -4 and 9

Explanation:

First, you want to get the equation to equal 0.

`x^(2) - 36 = 5x` subtract 5x from both sides to make the equation equal to 0.

`x^(2) -5x - 36 =0`

Now you are going to want to factor the equation

Find factors that add up to 5

`(x+4)(x-9)` I used 4 and 9 because they multiply to be 36, since 36 is negative that means that one of the numbers has to be negative. I made 9 negative because when you add 4 it equals 5.

Make both equations equal to 0

`x+4=0`

`-4`
`-4` subtract 4 from both sides to get x alone

`x = -4`

`x-9=0`

`+9`
`+9` add 9 to both sides to get x alone

`x=9`