-3x(2x-5)=15-6x

Solution for -3x(2x-5)=15-6x equation:

-3x(2x-5)=15-6x

We move all terms to the left:

-3x(2x-5)-(15-6x)=0

We add all the numbers together, and all the variables

-3x(2x-5)-(-6x+15)=0

We multiply parentheses

-6x^2+15x-(-6x+15)=0

We get rid of parentheses

-6x^2+15x+6x-15=0

We add all the numbers together, and all the variables

-6x^2+21x-15=0

a = -6; b = 21; c = -15;
Δ = b2-4ac
Δ = 212-4·(-6)·(-15)
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-9}{2*-6}=\frac{-30}{-12}
=2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+9}{2*-6}=\frac{-12}{-12}
=1
$