X2+1.5x=13.5

Solution for X2+1.5x=13.5 equation:

X2+1.5X=13.5

We move all terms to the left:

X2+1.5X-(13.5)=0

We add all the numbers together, and all the variables

X^2+1.5X-13.5=0

a = 1; b = 1.5; c = -13.5;
Δ = b2-4ac
Δ = 1.52-4·1·(-13.5)
Δ = 56.25
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{-(1.5)-\sqrt{56.25}}{2*1}=\frac{-1.5-\sqrt{56.25}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.5)+\sqrt{56.25}}{2*1}=\frac{-1.5+\sqrt{56.25}}{2}
$