720=4t^2

Solution for 720=4t^2 equation:

720=4t^2

We move all terms to the left:

720-(4t^2)=0

a = -4; b = 0; c = +720;
Δ = b2-4ac
Δ = 02-4·(-4)·720
Δ = 11520
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:

$\sqrt{\Delta}=\sqrt{11520}=\sqrt{2304*5}=\sqrt{2304}*\sqrt{5}=48\sqrt{5}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-48\sqrt{5}}{2*-4}=\frac{0-48\sqrt{5}}{-8}
=-\frac{48\sqrt{5}}{-8}
=-\frac{6\sqrt{5}}{-1}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+48\sqrt{5}}{2*-4}=\frac{0+48\sqrt{5}}{-8}
=\frac{48\sqrt{5}}{-8}
=\frac{6\sqrt{5}}{-1}
$