0=-16t^2+15t+25

Solution for 0=-16t^2+15t+25 equation:

0=-16t^2+15t+25

We move all terms to the left:

0-(-16t^2+15t+25)=0

We add all the numbers together, and all the variables

-(-16t^2+15t+25)=0

We get rid of parentheses

16t^2-15t-25=0

a = 16; b = -15; c = -25;
Δ = b2-4ac
Δ = -152-4·16·(-25)
Δ = 1825
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:

$\sqrt{\Delta}=\sqrt{1825}=\sqrt{25*73}=\sqrt{25}*\sqrt{73}=5\sqrt{73}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-5\sqrt{73}}{2*16}=\frac{15-5\sqrt{73}}{32}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+5\sqrt{73}}{2*16}=\frac{15+5\sqrt{73}}{32}
$