x^2+2x=1.56

Solution for x^2+2x=1.56 equation:

Simplifying
x2 + 2x = 1.56

Reorder the terms:
2x + x2 = 1.56

Solving
2x + x2 = 1.56

Solving for variable 'x'.

Reorder the terms:
-1.56 + 2x + x2 = 1.56 + -1.56

Combine like terms: 1.56 + -1.56 = 0.00
-1.56 + 2x + x2 = 0.00

Begin completing the square.

Move the constant term to the right:

Add '1.56' to each side of the equation.
-1.56 + 2x + 1.56 + x2 = 0.00 + 1.56

Reorder the terms:
-1.56 + 1.56 + 2x + x2 = 0.00 + 1.56

Combine like terms: -1.56 + 1.56 = 0.00
0.00 + 2x + x2 = 0.00 + 1.56
2x + x2 = 0.00 + 1.56

Combine like terms: 0.00 + 1.56 = 1.56
2x + x2 = 1.56

The x term is 2x.  Take half its coefficient (1).
Square it (1) and add it to both sides.

Add '1' to each side of the equation.
2x + 1 + x2 = 1.56 + 1

Reorder the terms:
1 + 2x + x2 = 1.56 + 1

Combine like terms: 1.56 + 1 = 2.56
1 + 2x + x2 = 2.56

Factor a perfect square on the left side:
(x + 1)(x + 1) = 2.56

Calculate the square root of the right side: 1.6

Break this problem into two subproblems by setting 
(x + 1) equal to 1.6 and -1.6.

Subproblem 1
x + 1 = 1.6

Simplifying
x + 1 = 1.6

Reorder the terms:
1 + x = 1.6

Solving
1 + x = 1.6

Solving for variable 'x'.

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

Add '-1' to each side of the equation.
1 + -1 + x = 1.6 + -1

Combine like terms: 1 + -1 = 0
0 + x = 1.6 + -1
x = 1.6 + -1

Combine like terms: 1.6 + -1 = 0.6
x = 0.6

Simplifying
x = 0.6

Subproblem 2
x + 1 = -1.6

Simplifying
x + 1 = -1.6

Reorder the terms:
1 + x = -1.6

Solving
1 + x = -1.6

Solving for variable 'x'.

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

Add '-1' to each side of the equation.
1 + -1 + x = -1.6 + -1

Combine like terms: 1 + -1 = 0
0 + x = -1.6 + -1
x = -1.6 + -1

Combine like terms: -1.6 + -1 = -2.6
x = -2.6

Simplifying
x = -2.6

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {0.6, -2.6}