40x2-30x=135

Solution for 40x2-30x=135 equation:

40x^2-30x=135

We move all terms to the left:

40x^2-30x-(135)=0

a = 40; b = -30; c = -135;
Δ = b2-4ac
Δ = -302-4·40·(-135)
Δ = 22500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{22500}=150$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-150}{2*40}=\frac{-120}{80}
=-1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+150}{2*40}=\frac{180}{80}
=2+1/4
$