66=2x^2+16x

Solution for 66=2x^2+16x equation:

66=2x^2+16x

We move all terms to the left:

66-(2x^2+16x)=0

We get rid of parentheses

-2x^2-16x+66=0

a = -2; b = -16; c = +66;
Δ = b2-4ac
Δ = -162-4·(-2)·66
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-28}{2*-2}=\frac{-12}{-4}
=+3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+28}{2*-2}=\frac{44}{-4}
=-11
$