3x^2-8x=128

Solution for 3x^2-8x=128 equation:

3x^2-8x=128

We move all terms to the left:

3x^2-8x-(128)=0

a = 3; b = -8; c = -128;
Δ = b2-4ac
Δ = -82-4·3·(-128)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-40}{2*3}=\frac{-32}{6}
=-5+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+40}{2*3}=\frac{48}{6}
=8
$