(7t^2+3t+-9)+(2t^2+6t)=

Solution for (7t^2+3t+-9)+(2t^2+6t)= equation:

Simplifying
(7t2 + 3t + -9) + (2t2 + 6t) = 0

Reorder the terms:
(-9 + 3t + 7t2) + (2t2 + 6t) = 0

Remove parenthesis around (-9 + 3t + 7t2)
-9 + 3t + 7t2 + (2t2 + 6t) = 0

Reorder the terms:
-9 + 3t + 7t2 + (6t + 2t2) = 0

Remove parenthesis around (6t + 2t2)
-9 + 3t + 7t2 + 6t + 2t2 = 0

Reorder the terms:
-9 + 3t + 6t + 7t2 + 2t2 = 0

Combine like terms: 3t + 6t = 9t
-9 + 9t + 7t2 + 2t2 = 0

Combine like terms: 7t2 + 2t2 = 9t2
-9 + 9t + 9t2 = 0

Solving
-9 + 9t + 9t2 = 0

Solving for variable 't'.

Factor out the Greatest Common Factor (GCF), '9'.
9(-1 + t + t2) = 0

Ignore the factor 9.
Subproblem 1
Set the factor '(-1 + t + t2)' equal to zero and attempt to solve:

Simplifying
-1 + t + t2 = 0

Solving
-1 + t + t2 = 0

Begin completing the square.

Move the constant term to the right:

Add '1' to each side of the equation.
-1 + t + 1 + t2 = 0 + 1

Reorder the terms:
-1 + 1 + t + t2 = 0 + 1

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

Combine like terms: 0 + 1 = 1
t + t2 = 1

The t term is t.  Take half its coefficient (0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
t + 0.25 + t2 = 1 + 0.25

Reorder the terms:
0.25 + t + t2 = 1 + 0.25

Combine like terms: 1 + 0.25 = 1.25
0.25 + t + t2 = 1.25

Factor a perfect square on the left side:
(t + 0.5)(t + 0.5) = 1.25

Calculate the square root of the right side: 1.118033989

Break this problem into two subproblems by setting 
(t + 0.5) equal to 1.118033989 and -1.118033989.

Subproblem 1
t + 0.5 = 1.118033989

Simplifying
t + 0.5 = 1.118033989

Reorder the terms:
0.5 + t = 1.118033989

Solving
0.5 + t = 1.118033989

Solving for variable 't'.

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

Add '-0.5' to each side of the equation.
0.5 + -0.5 + t = 1.118033989 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + t = 1.118033989 + -0.5
t = 1.118033989 + -0.5

Combine like terms: 1.118033989 + -0.5 = 0.618033989
t = 0.618033989

Simplifying
t = 0.618033989

Subproblem 2
t + 0.5 = -1.118033989

Simplifying
t + 0.5 = -1.118033989

Reorder the terms:
0.5 + t = -1.118033989

Solving
0.5 + t = -1.118033989

Solving for variable 't'.

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

Add '-0.5' to each side of the equation.
0.5 + -0.5 + t = -1.118033989 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + t = -1.118033989 + -0.5
t = -1.118033989 + -0.5

Combine like terms: -1.118033989 + -0.5 = -1.618033989
t = -1.618033989

Simplifying
t = -1.618033989

Solution
The solution to the problem is based on the solutions
from the subproblems.
t = {0.618033989, -1.618033989}
Solution
t = {0.618033989, -1.618033989}