0=64-t-5t^2

Solution for 0=64-t-5t^2 equation:

0=64-t-5t^2

We move all terms to the left:

0-(64-t-5t^2)=0

We add all the numbers together, and all the variables

-(64-t-5t^2)=0

We get rid of parentheses

5t^2+t-64=0

a = 5; b = 1; c = -64;
Δ = b2-4ac
Δ = 12-4·5·(-64)
Δ = 1281
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-\sqrt{1281}}{2*5}=\frac{-1-\sqrt{1281}}{10}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{1281}}{2*5}=\frac{-1+\sqrt{1281}}{10}
$