x2+1.2x=11

Solution for x2+1.2x=11 equation:

x2+1.2x=11

We move all terms to the left:

x2+1.2x-(11)=0

We add all the numbers together, and all the variables

x^2+1.2x-11=0

a = 1; b = 1.2; c = -11;
Δ = b2-4ac
Δ = 1.22-4·1·(-11)
Δ = 45.44
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1.2)-\sqrt{45.44}}{2*1}=\frac{-1.2-\sqrt{45.44}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.2)+\sqrt{45.44}}{2*1}=\frac{-1.2+\sqrt{45.44}}{2}
$