Answer
{$-10,8$}
Work Step by Step
Step 1: Comparing $x^{2}+2x-80=0$ to the standard form of a quadratic equation, $ax^{2}+bx+c=0$, we obtain:
$a=1$, $b=2$, and $c=-80$
Step 2: The quadratic formula is:
$x=\frac{-b \pm \sqrt {b^{2}-4ac}}{2a}$
Step 3: Substituting the values of a,b, and c in the formula, we obtain:
$x=\frac{-(2) \pm \sqrt {(2)^{2}-4(1)(-80)}}{2(1)}$
Step 4: $x=\frac{-2 \pm \sqrt {4+320}}{2}$
Step 5: $x=\frac{-2 \pm \sqrt {324}}{2}$
Step 6: $x=\frac{-2 \pm 18}{2}$
Step 7: $x=\frac{-2+18}{2}$ or $x=\frac{-2-18}{2}$
Step 8: $x=\frac{16}{2}$ or $x=\frac{-20}{2}$
Step 9: $x=8$ or $x=-10$
Step 10: Therefore, the solution set is {$-10,8$}.
