60t=40t-5t^2

Solution for 60t=40t-5t^2 equation:

60t=40t-5t^2

We move all terms to the left:

60t-(40t-5t^2)=0

We get rid of parentheses

5t^2-40t+60t=0

We add all the numbers together, and all the variables

5t^2+20t=0

a = 5; b = 20; c = 0;
Δ = b2-4ac
Δ = 202-4·5·0
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-20}{2*5}=\frac{-40}{10}
=-4
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+20}{2*5}=\frac{0}{10}
=0
$