5a^2+6a=-8

Solution for 5a^2+6a=-8 equation:

Simplifying
5a2 + 6a = -8

Reorder the terms:
6a + 5a2 = -8

Solving
6a + 5a2 = -8

Solving for variable 'a'.

Reorder the terms:
8 + 6a + 5a2 = -8 + 8

Combine like terms: -8 + 8 = 0
8 + 6a + 5a2 = 0

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

Divide each side by '5'.
1.6 + 1.2a + a2 = 0

Move the constant term to the right:

Add '-1.6' to each side of the equation.
1.6 + 1.2a + -1.6 + a2 = 0 + -1.6

Reorder the terms:
1.6 + -1.6 + 1.2a + a2 = 0 + -1.6

Combine like terms: 1.6 + -1.6 = 0.0
0.0 + 1.2a + a2 = 0 + -1.6
1.2a + a2 = 0 + -1.6

Combine like terms: 0 + -1.6 = -1.6
1.2a + a2 = -1.6

The a term is 1.2a.  Take half its coefficient (0.6).
Square it (0.36) and add it to both sides.

Add '0.36' to each side of the equation.
1.2a + 0.36 + a2 = -1.6 + 0.36

Reorder the terms:
0.36 + 1.2a + a2 = -1.6 + 0.36

Combine like terms: -1.6 + 0.36 = -1.24
0.36 + 1.2a + a2 = -1.24

Factor a perfect square on the left side:
(a + 0.6)(a + 0.6) = -1.24

Can't calculate square root of the right side.

The solution to this equation could not be determined.