Question

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

0 -9 and -4
O4 and 9
O4 and -9
o 9 and 4

Answer 1

-4 and 9

Explanation:

we have

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

we know that

The formula to solve a quadratic equation of the form

`ax^(2) +bx+c=0`

is equal to

`x=\frac{-b(+/-)\sqrt{b^(2)-4ac}} {2a}`

in this problem we have

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

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

so

`a=1\\b=-5\\c=-36`

substitute in the formula

`x=\frac{-(-5)(+/-)\sqrt{-5^(2)-4(1)(-36)}} {2(1)}`

`x=\frac{5(+/-)√(169)} {2}`

`x=\frac{5(+/-)13} {2}`

`x=\frac{5(+)13} {2}=9`

`x=\frac{5(-)13} {2}=-4`

therefore

The equation is true for -4 and 9