0=7t^2-13t-2

Solution for 0=7t^2-13t-2 equation:

0=7t^2-13t-2

We move all terms to the left:

0-(7t^2-13t-2)=0

We add all the numbers together, and all the variables

-(7t^2-13t-2)=0

We get rid of parentheses

-7t^2+13t+2=0

a = -7; b = 13; c = +2;
Δ = b2-4ac
Δ = 132-4·(-7)·2
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-15}{2*-7}=\frac{-28}{-14}
=+2
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+15}{2*-7}=\frac{2}{-14}
=-1/7
$