Question

How do you solve `x^2+10x-9=0`?

Answer 1

`x=-5+-sqrt(34)`

Explanation:

`x^2+10x-9=0`

is in the form:

`ax^2+bx+c=0`

where `a=1`, `b=10` and `c=-9`

Use the quadratic formula to find:

`x = (-b+-sqrt(b^2-4ac))/(2a)`

`color(white)(x) = (-10+-sqrt(10^2-4(1)(-9)))/(2*1)`

`color(white)(x) = (-10+-sqrt(100+36))/2`

`color(white)(x) = (-10+-sqrt(136))/2`

`color(white)(x) = (-10+-sqrt(2^2*34))/2`

`color(white)(x) = (-10+-2sqrt(34))/2`

`color(white)(x) = -5+-sqrt(34)`