4x(2x=30)

Solution for 4x(2x=30) equation:

4x(2x=30)

We move all terms to the left:

4x(2x-(30))=0

We multiply parentheses

8x^2-120x=0

a = 8; b = -120; c = 0;
Δ = b2-4ac
Δ = -1202-4·8·0
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*8}=\frac{0}{16}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-120)+120}{2*8}=\frac{240}{16}
=15
$