240-12x=1,2x^2

Solution for 240-12x=1,2x^2 equation:

240-12x=1.2x^2

We move all terms to the left:

240-12x-(1.2x^2)=0

We get rid of parentheses

-1.2x^2-12x+240=0

a = -1.2; b = -12; c = +240;
Δ = b2-4ac
Δ = -122-4·(-1.2)·240
Δ = 1296
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1296}=36$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-36}{2*-1.2}=\frac{-24}{-2.4}
=+10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+36}{2*-1.2}=\frac{48}{-2.4}
=-20
$