x=3x*(x-30)+3*(x-25)

Solution for x=3x*(x-30)+3*(x-25) equation:

x=3x(x-30)+3(x-25)

We move all terms to the left:

x-(3x(x-30)+3(x-25))=0


We calculate terms in parentheses: -(3x(x-30)+3(x-25)), so:

3x(x-30)+3(x-25)

We multiply parentheses

3x^2-90x+3x-75

We add all the numbers together, and all the variables

3x^2-87x-75

Back to the equation:

-(3x^2-87x-75)


We get rid of parentheses

-3x^2+x+87x+75=0

We add all the numbers together, and all the variables

-3x^2+88x+75=0

a = -3; b = 88; c = +75;
Δ = b2-4ac
Δ = 882-4·(-3)·75
Δ = 8644
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{8644}=\sqrt{4*2161}=\sqrt{4}*\sqrt{2161}=2\sqrt{2161}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(88)-2\sqrt{2161}}{2*-3}=\frac{-88-2\sqrt{2161}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(88)+2\sqrt{2161}}{2*-3}=\frac{-88+2\sqrt{2161}}{-6}
$