126=x(2x-4)

Solution for 126=x(2x-4) equation:

126=x(2x-4)

We move all terms to the left:

126-(x(2x-4))=0


We calculate terms in parentheses: -(x(2x-4)), so:

x(2x-4)

We multiply parentheses

2x^2-4x

Back to the equation:

-(2x^2-4x)


We get rid of parentheses

-2x^2+4x+126=0

a = -2; b = 4; c = +126;
Δ = b2-4ac
Δ = 42-4·(-2)·126
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-32}{2*-2}=\frac{-36}{-4}
=+9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+32}{2*-2}=\frac{28}{-4}
=-7
$