64=8t^2-40t-224

Solution for 64=8t^2-40t-224 equation:

64=8t^2-40t-224

We move all terms to the left:

64-(8t^2-40t-224)=0

We get rid of parentheses

-8t^2+40t+224+64=0

We add all the numbers together, and all the variables

-8t^2+40t+288=0

a = -8; b = 40; c = +288;
Δ = b2-4ac
Δ = 402-4·(-8)·288
Δ = 10816
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{10816}=104$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-104}{2*-8}=\frac{-144}{-16}
=+9
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+104}{2*-8}=\frac{64}{-16}
=-4
$