(2x+4)x-16=90

Solution for (2x+4)x-16=90 equation:

(2x+4)x-16=90

We move all terms to the left:

(2x+4)x-16-(90)=0

We add all the numbers together, and all the variables

(2x+4)x-106=0

We multiply parentheses

2x^2+4x-106=0

a = 2; b = 4; c = -106;
Δ = b2-4ac
Δ = 42-4·2·(-106)
Δ = 864
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{864}=\sqrt{144*6}=\sqrt{144}*\sqrt{6}=12\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-12\sqrt{6}}{2*2}=\frac{-4-12\sqrt{6}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+12\sqrt{6}}{2*2}=\frac{-4+12\sqrt{6}}{4}
$