(x^2+x+15)+(x^2+x+6)=

Solution for (x^2+x+15)+(x^2+x+6)= equation:

Simplifying
(x2 + x + 15) + (x2 + x + 6) = 0

Reorder the terms:
(15 + x + x2) + (x2 + x + 6) = 0

Remove parenthesis around (15 + x + x2)
15 + x + x2 + (x2 + x + 6) = 0

Reorder the terms:
15 + x + x2 + (6 + x + x2) = 0

Remove parenthesis around (6 + x + x2)
15 + x + x2 + 6 + x + x2 = 0

Reorder the terms:
15 + 6 + x + x + x2 + x2 = 0

Combine like terms: 15 + 6 = 21
21 + x + x + x2 + x2 = 0

Combine like terms: x + x = 2x
21 + 2x + x2 + x2 = 0

Combine like terms: x2 + x2 = 2x2
21 + 2x + 2x2 = 0

Solving
21 + 2x + 2x2 = 0

Solving for variable 'x'.

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

Divide each side by '2'.
10.5 + x + x2 = 0

Move the constant term to the right:

Add '-10.5' to each side of the equation.
10.5 + x + -10.5 + x2 = 0 + -10.5

Reorder the terms:
10.5 + -10.5 + x + x2 = 0 + -10.5

Combine like terms: 10.5 + -10.5 = 0.0
0.0 + x + x2 = 0 + -10.5
x + x2 = 0 + -10.5

Combine like terms: 0 + -10.5 = -10.5
x + x2 = -10.5

The x term is x.  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.
 + 0.25 + x2 = -10.5 + 0.25

Combine like terms:  + 0.25 = 1.25
1.25 + x2 = -10.5 + 0.25

Combine like terms: -10.5 + 0.25 = -10.25
1.25 + x2 = -10.25

Factor a perfect square on the left side:
(x + 0.5)(x + 0.5) = -10.25

Can't calculate square root of the right side.

The solution to this equation could not be determined.