360=48t-0.8t^2

Solution for 360=48t-0.8t^2 equation:

360=48t-0.8t^2

We move all terms to the left:

360-(48t-0.8t^2)=0

We get rid of parentheses

0.8t^2-48t+360=0

a = 0.8; b = -48; c = +360;
Δ = b2-4ac
Δ = -482-4·0.8·360
Δ = 1152
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:

$\sqrt{\Delta}=\sqrt{1152}=\sqrt{576*2}=\sqrt{576}*\sqrt{2}=24\sqrt{2}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-48)-24\sqrt{2}}{2*0.8}=\frac{48-24\sqrt{2}}{1.6}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-48)+24\sqrt{2}}{2*0.8}=\frac{48+24\sqrt{2}}{1.6}
$