750-30t^2-60t=0

Solution for 750-30t^2-60t=0 equation:

750-30t^2-60t=0

a = -30; b = -60; c = +750;
Δ = b2-4ac
Δ = -602-4·(-30)·750
Δ = 93600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{93600}=\sqrt{3600*26}=\sqrt{3600}*\sqrt{26}=60\sqrt{26}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-60\sqrt{26}}{2*-30}=\frac{60-60\sqrt{26}}{-60}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+60\sqrt{26}}{2*-30}=\frac{60+60\sqrt{26}}{-60}
$