4x^2-6x=40

Solution for 4x^2-6x=40 equation:

4x^2-6x=40

We move all terms to the left:

4x^2-6x-(40)=0

a = 4; b = -6; c = -40;
Δ = b2-4ac
Δ = -62-4·4·(-40)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-26}{2*4}=\frac{-20}{8}
=-2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+26}{2*4}=\frac{32}{8}
=4
$