Question

What are the roots of the equation x squared plus 6x subtracted by 9 equals 0

Answer 1

`x=-3(+/-)3√(2)`

Explanation:

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) +6x-9=0`

so

`a=1\\b=6\\c=-9`

substitute in the formula

`x=\frac{-6(+/-)\sqrt{6^(2)-4(1)(-9)}} {2(1)}`

`x=\frac{-6(+/-)√(72)} {2}`

`x=\frac{-6(+/-)6√(2)} {2}`

`x=-3(+/-)3√(2)`