20f^2-110f+90=0

Solution for 20f^2-110f+90=0 equation:

20f^2-110f+90=0

a = 20; b = -110; c = +90;
Δ = b2-4ac
Δ = -1102-4·20·90
Δ = 4900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4900}=70$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-110)-70}{2*20}=\frac{40}{40}
=1
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-110)+70}{2*20}=\frac{180}{40}
=4+1/2
$