120=2x(x+11)

Solution for 120=2x(x+11) equation:

120=2x(x+11)

We move all terms to the left:

120-(2x(x+11))=0


We calculate terms in parentheses: -(2x(x+11)), so:

2x(x+11)

We multiply parentheses

2x^2+22x

Back to the equation:

-(2x^2+22x)


We get rid of parentheses

-2x^2-22x+120=0

a = -2; b = -22; c = +120;
Δ = b2-4ac
Δ = -222-4·(-2)·120
Δ = 1444
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1444}=38$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-22)-38}{2*-2}=\frac{-16}{-4}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-22)+38}{2*-2}=\frac{60}{-4}
=-15
$