2(x+5)8x+15=90

Solution for 2(x+5)8x+15=90 equation:

2(x+5)8x+15=90

We move all terms to the left:

2(x+5)8x+15-(90)=0

We add all the numbers together, and all the variables

2(x+5)8x-75=0

We multiply parentheses

16x^2+80x-75=0

a = 16; b = 80; c = -75;
Δ = b2-4ac
Δ = 802-4·16·(-75)
Δ = 11200
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:

$\sqrt{\Delta}=\sqrt{11200}=\sqrt{1600*7}=\sqrt{1600}*\sqrt{7}=40\sqrt{7}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-40\sqrt{7}}{2*16}=\frac{-80-40\sqrt{7}}{32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+40\sqrt{7}}{2*16}=\frac{-80+40\sqrt{7}}{32}
$