7m^2+14m-245=0

Solution for 7m^2+14m-245=0 equation:

7m^2+14m-245=0

a = 7; b = 14; c = -245;
Δ = b2-4ac
Δ = 142-4·7·(-245)
Δ = 7056
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7056}=84$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(14)-84}{2*7}=\frac{-98}{14}
=-7
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+84}{2*7}=\frac{70}{14}
=5
$