2m^2+13m+21=0

Solution for 2m^2+13m+21=0 equation:

2m^2+13m+21=0

a = 2; b = 13; c = +21;
Δ = b2-4ac
Δ = 132-4·2·21
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-1}{2*2}=\frac{-14}{4}
=-3+1/2
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+1}{2*2}=\frac{-12}{4}
=-3
$