(4x+8)x0=90

Solution for (4x+8)x0=90 equation:

(4x+8)x0=90

We move all terms to the left:

(4x+8)x0-(90)=0

We multiply parentheses

4x^2+8x-90=0

a = 4; b = 8; c = -90;
Δ = b2-4ac
Δ = 82-4·4·(-90)
Δ = 1504
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:

$\sqrt{\Delta}=\sqrt{1504}=\sqrt{16*94}=\sqrt{16}*\sqrt{94}=4\sqrt{94}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-4\sqrt{94}}{2*4}=\frac{-8-4\sqrt{94}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+4\sqrt{94}}{2*4}=\frac{-8+4\sqrt{94}}{8}
$