0.525x^2+2.25x+0.8=0

Solution for 0.525x^2+2.25x+0.8=0 equation:

0.525x^2+2.25x+0.8=0

a = 0.525; b = 2.25; c = +0.8;
Δ = b2-4ac
Δ = 2.252-4·0.525·0.8
Δ = 3.3825
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{-(2.25)-\sqrt{3.3825}}{2*0.525}=\frac{-2.25-\sqrt{3.3825}}{1.05}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.25)+\sqrt{3.3825}}{2*0.525}=\frac{-2.25+\sqrt{3.3825}}{1.05}
$