100=20t+(-1)t^2

Solution for 100=20t+(-1)t^2 equation:

Simplifying
100 = 20t + (-1) * t2

Solving
100 = 20t + -1t2

Solving for variable 't'.

Reorder the terms:
100 + -20t + t2 = 20t + -20t + -1t2 + t2

Combine like terms: 20t + -20t = 0
100 + -20t + t2 = 0 + -1t2 + t2
100 + -20t + t2 = -1t2 + t2

Combine like terms: -1t2 + t2 = 0
100 + -20t + t2 = 0

Factor a trinomial.
(10 + -1t)(10 + -1t) = 0

Subproblem 1
Set the factor '(10 + -1t)' equal to zero and attempt to solve:

Simplifying
10 + -1t = 0

Solving
10 + -1t = 0

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

Add '-10' to each side of the equation.
10 + -10 + -1t = 0 + -10

Combine like terms: 10 + -10 = 0
0 + -1t = 0 + -10
-1t = 0 + -10

Combine like terms: 0 + -10 = -10
-1t = -10

Divide each side by '-1'.
t = 10

Simplifying
t = 10
Subproblem 2
Set the factor '(10 + -1t)' equal to zero and attempt to solve:

Simplifying
10 + -1t = 0

Solving
10 + -1t = 0

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

Add '-10' to each side of the equation.
10 + -10 + -1t = 0 + -10

Combine like terms: 10 + -10 = 0
0 + -1t = 0 + -10
-1t = 0 + -10

Combine like terms: 0 + -10 = -10
-1t = -10

Divide each side by '-1'.
t = 10

Simplifying
t = 10
Solution
t = {10, 10}