Question

How do you evaluate `\sqrt { x ^ { 2} + 2x - 8}`?

Answer 1

Assuming you meant "evaluate `sqrt(x^2+2x-8)=0`" for `x`
then `x=4` or `x=-2`

Explanation:

If
`color(white)("XXX")sqrt(x^2-2x-8)=0`
then
`color(white)("XXX")x^2-2x-8=0`

The left side can be factored as
`color(white)("XXX")(x-4)(x+2)=0`
which implies
`color(white)("XXX")x=4color(white)("xx")"or"color(white)("xx")x=-2`