0=-16t^2+76t+20

Solution for 0=-16t^2+76t+20 equation:

0=-16t^2+76t+20

We move all terms to the left:

0-(-16t^2+76t+20)=0

We add all the numbers together, and all the variables

-(-16t^2+76t+20)=0

We get rid of parentheses

16t^2-76t-20=0

a = 16; b = -76; c = -20;
Δ = b2-4ac
Δ = -762-4·16·(-20)
Δ = 7056
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7056}=84$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-76)-84}{2*16}=\frac{-8}{32}
=-1/4
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-76)+84}{2*16}=\frac{160}{32}
=5
$