0,2a^2+3,4a+7,2=0

Solution for 0,2a^2+3,4a+7,2=0 equation:

0.2a^2+3.4a+7.2=0

a = 0.2; b = 3.4; c = +7.2;
Δ = b2-4ac
Δ = 3.42-4·0.2·7.2
Δ = 5.8
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3.4)-\sqrt{5.8}}{2*0.2}=\frac{-3.4-\sqrt{5.8}}{0.4}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3.4)+\sqrt{5.8}}{2*0.2}=\frac{-3.4+\sqrt{5.8}}{0.4}
$