9t^2-72t-25=0

Solution for 9t^2-72t-25=0 equation:

9t^2-72t-25=0

a = 9; b = -72; c = -25;
Δ = b2-4ac
Δ = -722-4·9·(-25)
Δ = 6084
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6084}=78$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-72)-78}{2*9}=\frac{-6}{18}
=-1/3
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-72)+78}{2*9}=\frac{150}{18}
=8+1/3
$