5=2+3.3x-0,75x^2

Solution for 5=2+3.3x-0,75x^2 equation:

5=2+3.3x-0.75x^2

We move all terms to the left:

5-(2+3.3x-0.75x^2)=0

We get rid of parentheses

0.75x^2-3.3x-2+5=0

We add all the numbers together, and all the variables

0.75x^2-3.3x+3=0

a = 0.75; b = -3.3; c = +3;
Δ = b2-4ac
Δ = -3.32-4·0.75·3
Δ = 1.89
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{-(-3.3)-\sqrt{1.89}}{2*0.75}=\frac{3.3-\sqrt{1.89}}{1.5}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3.3)+\sqrt{1.89}}{2*0.75}=\frac{3.3+\sqrt{1.89}}{1.5}
$