Question

How do you solve using the quadratic formula `x^2 - 5x - 8 = 0`?

Answer 1

`x_1=5/2pmsqrt(57)/2`

Explanation:

using the formula for

`x^2+px+q=0`
`x_(1,2)=-p/2pmsqrt(p^2/4-q)`
so we get for `p=-5,q=-8`
`x_(1,2)=5/2pmsqrt(25/4+8)`
Note that

`25/4+8=(25+32)/4=57/4`

`x_(1,2)=5/2pmsqrt(57)/2`