-45=10t-((.5)(-9.8)t^2)

Solution for -45=10t-((.5)(-9.8)t^2) equation:

Simplifying
-45 = 10t + -1((0.5)(-9.8) * t2)

Multiply 0.5 * -9.8
-45 = 10t + -1(-4.9t2)

Remove parenthesis around (-4.9t2)
-45 = 10t + -1 * -4.9t2

Multiply -1 * -4.9
-45 = 10t + 4.9t2

Solving
-45 = 10t + 4.9t2

Solving for variable 't'.

Reorder the terms:
-45 + -10t + -4.9t2 = 10t + -10t + 4.9t2 + -4.9t2

Combine like terms: 10t + -10t = 0
-45 + -10t + -4.9t2 = 0 + 4.9t2 + -4.9t2
-45 + -10t + -4.9t2 = 4.9t2 + -4.9t2

Combine like terms: 4.9t2 + -4.9t2 = 0.0
-45 + -10t + -4.9t2 = 0.0

Begin completing the square.  Divide all terms by
-4.9 the coefficient of the squared term: 

Divide each side by '-4.9'.
9.183673469 + 2.040816327t + t2 = 0

Move the constant term to the right:

Add '-9.183673469' to each side of the equation.
9.183673469 + 2.040816327t + -9.183673469 + t2 = 0 + -9.183673469

Reorder the terms:
9.183673469 + -9.183673469 + 2.040816327t + t2 = 0 + -9.183673469

Combine like terms: 9.183673469 + -9.183673469 = 0.000000000
0.000000000 + 2.040816327t + t2 = 0 + -9.183673469
2.040816327t + t2 = 0 + -9.183673469

Combine like terms: 0 + -9.183673469 = -9.183673469
2.040816327t + t2 = -9.183673469

The t term is 2.040816327t.  Take half its coefficient (1.020408164).
Square it (1.041232821) and add it to both sides.

Add '1.041232821' to each side of the equation.
2.040816327t + 1.041232821 + t2 = -9.183673469 + 1.041232821

Reorder the terms:
1.041232821 + 2.040816327t + t2 = -9.183673469 + 1.041232821

Combine like terms: -9.183673469 + 1.041232821 = -8.142440648
1.041232821 + 2.040816327t + t2 = -8.142440648

Factor a perfect square on the left side:
(t + 1.020408164)(t + 1.020408164) = -8.142440648

Can't calculate square root of the right side.

The solution to this equation could not be determined.