4(15t-4t^2-15)=0

Solution for 4(15t-4t^2-15)=0 equation:

Simplifying
4(15t + -4t2 + -15) = 0

Reorder the terms:
4(-15 + 15t + -4t2) = 0
(-15 * 4 + 15t * 4 + -4t2 * 4) = 0
(-60 + 60t + -16t2) = 0

Solving
-60 + 60t + -16t2 = 0

Solving for variable 't'.

Factor out the Greatest Common Factor (GCF), '4'.
4(-15 + 15t + -4t2) = 0

Ignore the factor 4.
Subproblem 1
Set the factor '(-15 + 15t + -4t2)' equal to zero and attempt to solve:

Simplifying
-15 + 15t + -4t2 = 0

Solving
-15 + 15t + -4t2 = 0

Begin completing the square.  Divide all terms by
-4 the coefficient of the squared term: 

Divide each side by '-4'.
3.75 + -3.75t + t2 = 0

Move the constant term to the right:

Add '-3.75' to each side of the equation.
3.75 + -3.75t + -3.75 + t2 = 0 + -3.75

Reorder the terms:
3.75 + -3.75 + -3.75t + t2 = 0 + -3.75

Combine like terms: 3.75 + -3.75 = 0.00
0.00 + -3.75t + t2 = 0 + -3.75
-3.75t + t2 = 0 + -3.75

Combine like terms: 0 + -3.75 = -3.75
-3.75t + t2 = -3.75

The t term is -3.75t.  Take half its coefficient (-1.875).
Square it (3.515625) and add it to both sides.

Add '3.515625' to each side of the equation.
-3.75t + 3.515625 + t2 = -3.75 + 3.515625

Reorder the terms:
3.515625 + -3.75t + t2 = -3.75 + 3.515625

Combine like terms: -3.75 + 3.515625 = -0.234375
3.515625 + -3.75t + t2 = -0.234375

Factor a perfect square on the left side:
(t + -1.875)(t + -1.875) = -0.234375

Can't calculate square root of the right side.

The solution to this equation could not be determined.

This subproblem is being ignored because a solution could not be determined.

The solution to this equation could not be determined.