(8x-7)4x=15

Solution for (8x-7)4x=15 equation:

(8x-7)4x=15

We move all terms to the left:

(8x-7)4x-(15)=0

We multiply parentheses

32x^2-28x-15=0

a = 32; b = -28; c = -15;
Δ = b2-4ac
Δ = -282-4·32·(-15)
Δ = 2704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2704}=52$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-28)-52}{2*32}=\frac{-24}{64}
=-3/8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-28)+52}{2*32}=\frac{80}{64}
=1+1/4
$