Answer
$\bf graph(a)$
Work Step by Step
Given: $x^2+2x-8=0$
Need to use factorization to solve the quadratic equation.
This can be factorized as follows:
$x^2-2x+4x+8=0$
or, $(x-2)(x+4)=0$
Now $x-2=0$ and $x+4=0$
Roots are $x=2,-4$.
These values are represented by $\bf graph(a)$
