0=15t^2-120t

Solution for 0=15t^2-120t equation:

0=15t^2-120t

We move all terms to the left:

0-(15t^2-120t)=0

We add all the numbers together, and all the variables

-(15t^2-120t)=0

We get rid of parentheses

-15t^2+120t=0

a = -15; b = 120; c = 0;
Δ = b2-4ac
Δ = 1202-4·(-15)·0
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(120)-120}{2*-15}=\frac{-240}{-30}
=+8
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(120)+120}{2*-15}=\frac{0}{-30}
=0
$