20=60-16t^2

Solution for 20=60-16t^2 equation:

Simplifying
20 = 60 + -16t2

Solving
20 = 60 + -16t2

Solving for variable 't'.

Move all terms containing t to the left, all other terms to the right.

Add '16t2' to each side of the equation.
20 + 16t2 = 60 + -16t2 + 16t2

Combine like terms: -16t2 + 16t2 = 0
20 + 16t2 = 60 + 0
20 + 16t2 = 60

Add '-20' to each side of the equation.
20 + -20 + 16t2 = 60 + -20

Combine like terms: 20 + -20 = 0
0 + 16t2 = 60 + -20
16t2 = 60 + -20

Combine like terms: 60 + -20 = 40
16t2 = 40

Divide each side by '16'.
t2 = 2.5

Simplifying
t2 = 2.5

Take the square root of each side:
t = {-1.58113883, 1.58113883}