-25m^2+400=0

Solution for -25m^2+400=0 equation:

-25m^2+400=0

a = -25; b = 0; c = +400;
Δ = b2-4ac
Δ = 02-4·(-25)·400
Δ = 40000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{40000}=200$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-200}{2*-25}=\frac{-200}{-50}
=+4
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+200}{2*-25}=\frac{200}{-50}
=-4
$