123=4x2+60x-13

Solution for 123=4x2+60x-13 equation:

123=4x^2+60x-13

We move all terms to the left:

123-(4x^2+60x-13)=0

We get rid of parentheses

-4x^2-60x+13+123=0

We add all the numbers together, and all the variables

-4x^2-60x+136=0

a = -4; b = -60; c = +136;
Δ = b2-4ac
Δ = -602-4·(-4)·136
Δ = 5776
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5776}=76$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-76}{2*-4}=\frac{-16}{-8}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+76}{2*-4}=\frac{136}{-8}
=-17
$