0=4x(3x-15)

Solution for 0=4x(3x-15) equation:

0=4x(3x-15)

We move all terms to the left:

0-(4x(3x-15))=0

We add all the numbers together, and all the variables

-(4x(3x-15))=0


We calculate terms in parentheses: -(4x(3x-15)), so:

4x(3x-15)

We multiply parentheses

12x^2-60x

Back to the equation:

-(12x^2-60x)


We get rid of parentheses

-12x^2+60x=0

a = -12; b = 60; c = 0;
Δ = b2-4ac
Δ = 602-4·(-12)·0
Δ = 3600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3600}=60$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-60}{2*-12}=\frac{-120}{-24}
=+5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+60}{2*-12}=\frac{0}{-24}
=0
$