X2+2x-20+10x-50=90

Solution for X2+2x-20+10x-50=90 equation:

X2+2X-20+10X-50=90

We move all terms to the left:

X2+2X-20+10X-50-(90)=0

We add all the numbers together, and all the variables

X^2+12X-160=0

a = 1; b = 12; c = -160;
Δ = b2-4ac
Δ = 122-4·1·(-160)
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-28}{2*1}=\frac{-40}{2}
=-20
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+28}{2*1}=\frac{16}{2}
=8
$