-40x=16x^2+16

Solution for -40x=16x^2+16 equation:

-40x=16x^2+16

We move all terms to the left:

-40x-(16x^2+16)=0

We get rid of parentheses

-16x^2-40x-16=0

a = -16; b = -40; c = -16;
Δ = b2-4ac
Δ = -402-4·(-16)·(-16)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-24}{2*-16}=\frac{16}{-32}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+24}{2*-16}=\frac{64}{-32}
=-2
$