t=-15t2+60t+40

Solution for t=-15t2+60t+40 equation:

t=-15t^2+60t+40

We move all terms to the left:

t-(-15t^2+60t+40)=0

We get rid of parentheses

15t^2-60t+t-40=0

We add all the numbers together, and all the variables

15t^2-59t-40=0

a = 15; b = -59; c = -40;
Δ = b2-4ac
Δ = -592-4·15·(-40)
Δ = 5881
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{-(-59)-\sqrt{5881}}{2*15}=\frac{59-\sqrt{5881}}{30}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-59)+\sqrt{5881}}{2*15}=\frac{59+\sqrt{5881}}{30}
$