60-2t=-20+t+t^2

Solution for 60-2t=-20+t+t^2 equation:

60-2t=-20+t+t^2

We move all terms to the left:

60-2t-(-20+t+t^2)=0

We get rid of parentheses

-t^2-t-2t+20+60=0

We add all the numbers together, and all the variables

-1t^2-3t+80=0

a = -1; b = -3; c = +80;
Δ = b2-4ac
Δ = -32-4·(-1)·80
Δ = 329
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{329}}{2*-1}=\frac{3-\sqrt{329}}{-2}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+\sqrt{329}}{2*-1}=\frac{3+\sqrt{329}}{-2}
$