60=-16t2-64t

Solution for 60=-16t2-64t equation:

60=-16t^2-64t

We move all terms to the left:

60-(-16t^2-64t)=0

We get rid of parentheses

16t^2+64t+60=0

a = 16; b = 64; c = +60;
Δ = b2-4ac
Δ = 642-4·16·60
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(64)-16}{2*16}=\frac{-80}{32}
=-2+1/2
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(64)+16}{2*16}=\frac{-48}{32}
=-1+1/2
$