60x-2x^2-400=0

Solution for 60x-2x^2-400=0 equation:

60x-2x^2-400=0

a = -2; b = 60; c = -400;
Δ = b2-4ac
Δ = 602-4·(-2)·(-400)
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-20}{2*-2}=\frac{-80}{-4}
=+20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+20}{2*-2}=\frac{-40}{-4}
=+10
$