2x^2-x-30=123

Solution for 2x^2-x-30=123 equation:

2x^2-x-30=123

We move all terms to the left:

2x^2-x-30-(123)=0

We add all the numbers together, and all the variables

2x^2-1x-153=0

a = 2; b = -1; c = -153;
Δ = b2-4ac
Δ = -12-4·2·(-153)
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-35}{2*2}=\frac{-34}{4}
=-8+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+35}{2*2}=\frac{36}{4}
=9
$