25x-40x-16=25x^2-20x-20x-16+10x-30

Solution for 25x-40x-16=25x^2-20x-20x-16+10x-30 equation:

25x-40x-16=25x^2-20x-20x-16+10x-30

We move all terms to the left:

25x-40x-16-(25x^2-20x-20x-16+10x-30)=0

We add all the numbers together, and all the variables

-15x-(25x^2-20x-20x-16+10x-30)-16=0

We get rid of parentheses

-25x^2-15x+20x+20x-10x+16+30-16=0

We add all the numbers together, and all the variables

-25x^2+15x+30=0

a = -25; b = 15; c = +30;
Δ = b2-4ac
Δ = 152-4·(-25)·30
Δ = 3225
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:

$\sqrt{\Delta}=\sqrt{3225}=\sqrt{25*129}=\sqrt{25}*\sqrt{129}=5\sqrt{129}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-5\sqrt{129}}{2*-25}=\frac{-15-5\sqrt{129}}{-50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+5\sqrt{129}}{2*-25}=\frac{-15+5\sqrt{129}}{-50}
$