0=2t^2-3t-15

Solution for 0=2t^2-3t-15 equation:

0=2t^2-3t-15

We move all terms to the left:

0-(2t^2-3t-15)=0

We add all the numbers together, and all the variables

-(2t^2-3t-15)=0

We get rid of parentheses

-2t^2+3t+15=0

a = -2; b = 3; c = +15;
Δ = b2-4ac
Δ = 32-4·(-2)·15
Δ = 129
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{-(3)-\sqrt{129}}{2*-2}=\frac{-3-\sqrt{129}}{-4}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{129}}{2*-2}=\frac{-3+\sqrt{129}}{-4}
$