3x(2x=40)

Solution for 3x(2x=40) equation:

3x(2x=40)

We move all terms to the left:

3x(2x-(40))=0

We multiply parentheses

6x^2-120x=0

a = 6; b = -120; c = 0;
Δ = b2-4ac
Δ = -1202-4·6·0
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-120)-120}{2*6}=\frac{0}{12}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-120)+120}{2*6}=\frac{240}{12}
=20
$