10t^2-15t-25=0

Solution for 10t^2-15t-25=0 equation:

10t^2-15t-25=0

a = 10; b = -15; c = -25;
Δ = b2-4ac
Δ = -152-4·10·(-25)
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-35}{2*10}=\frac{-20}{20}
=-1
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+35}{2*10}=\frac{50}{20}
=2+1/2
$