-2u-20=-8u(u-2)

Solution for -2u-20=-8u(u-2) equation:

-2u-20=-8u(u-2)

We move all terms to the left:

-2u-20-(-8u(u-2))=0


We calculate terms in parentheses: -(-8u(u-2)), so:

-8u(u-2)

We multiply parentheses

-8u^2+16u

Back to the equation:

-(-8u^2+16u)


We get rid of parentheses

8u^2-16u-2u-20=0

We add all the numbers together, and all the variables

8u^2-18u-20=0

a = 8; b = -18; c = -20;
Δ = b2-4ac
Δ = -182-4·8·(-20)
Δ = 964
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{964}=\sqrt{4*241}=\sqrt{4}*\sqrt{241}=2\sqrt{241}$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-2\sqrt{241}}{2*8}=\frac{18-2\sqrt{241}}{16}
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+2\sqrt{241}}{2*8}=\frac{18+2\sqrt{241}}{16}
$