9=0*t+0.5*9.8*t*t

Solution for 9=0*t+0.5*9.8*t*t equation:

Simplifying
9 = 0t + 0.5 * 9.8t * t

Anything times zero is zero.
9 = 0t + 0.5 * 9.8t * t

Multiply 0.5 * 9.8
9 = 0 + 4.9t * t

Multiply t * t
9 = 0 + 4.9t2
Remove the zero:
9 = 4.9t2

Solving
9 = 4.9t2

Solving for variable 't'.

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

Add '-4.9t2' to each side of the equation.
9 + -4.9t2 = 4.9t2 + -4.9t2

Combine like terms: 4.9t2 + -4.9t2 = 0.0
9 + -4.9t2 = 0.0

Add '-9' to each side of the equation.
9 + -9 + -4.9t2 = 0.0 + -9

Combine like terms: 9 + -9 = 0
0 + -4.9t2 = 0.0 + -9
-4.9t2 = 0.0 + -9

Combine like terms: 0.0 + -9 = -9
-4.9t2 = -9

Divide each side by '-4.9'.
t2 = 1.836734694

Simplifying
t2 = 1.836734694

Take the square root of each side:
t = {-1.355261854, 1.355261854}