X2+5x-20=25-2x2-x

Solution for X2+5x-20=25-2x2-x equation:

X2+5X-20=25-2X^2-X

We move all terms to the left:

X2+5X-20-(25-2X^2-X)=0

We add all the numbers together, and all the variables

X^2-(25-2X^2-X)+5X-20=0

We get rid of parentheses

X^2+2X^2+X+5X-25-20=0

We add all the numbers together, and all the variables

3X^2+6X-45=0

a = 3; b = 6; c = -45;
Δ = b2-4ac
Δ = 62-4·3·(-45)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-24}{2*3}=\frac{-30}{6}
=-5
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+24}{2*3}=\frac{18}{6}
=3
$