20t^2-21+4=0

Solution for 20t^2-21+4=0 equation:

Simplifying
20t2 + -21 + 4 = 0

Reorder the terms:
-21 + 4 + 20t2 = 0

Combine like terms: -21 + 4 = -17
-17 + 20t2 = 0

Solving
-17 + 20t2 = 0

Solving for variable 't'.

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

Add '17' to each side of the equation.
-17 + 17 + 20t2 = 0 + 17

Combine like terms: -17 + 17 = 0
0 + 20t2 = 0 + 17
20t2 = 0 + 17

Combine like terms: 0 + 17 = 17
20t2 = 17

Divide each side by '20'.
t2 = 0.85

Simplifying
t2 = 0.85

Take the square root of each side:
t = {-0.921954446, 0.921954446}