5x^2-20x+7,2=0

Solution for 5x^2-20x+7,2=0 equation:

5x^2-20x+7.2=0

a = 5; b = -20; c = +7.2;
Δ = b2-4ac
Δ = -202-4·5·7.2
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-16}{2*5}=\frac{4}{10}
=2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+16}{2*5}=\frac{36}{10}
=3+3/5
$