x^2-0.7x-1.2=0

Solution for x^2-0.7x-1.2=0 equation:

Simplifying
x2 + -0.7x + -1.2 = 0

Reorder the terms:
-1.2 + -0.7x + x2 = 0

Solving
-1.2 + -0.7x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '1.2' to each side of the equation.
-1.2 + -0.7x + 1.2 + x2 = 0 + 1.2

Reorder the terms:
-1.2 + 1.2 + -0.7x + x2 = 0 + 1.2

Combine like terms: -1.2 + 1.2 = 0.0
0.0 + -0.7x + x2 = 0 + 1.2
-0.7x + x2 = 0 + 1.2

Combine like terms: 0 + 1.2 = 1.2
-0.7x + x2 = 1.2

The x term is -0.7x.  Take half its coefficient (-0.35).
Square it (0.1225) and add it to both sides.

Add '0.1225' to each side of the equation.
-0.7x + 0.1225 + x2 = 1.2 + 0.1225

Reorder the terms:
0.1225 + -0.7x + x2 = 1.2 + 0.1225

Combine like terms: 1.2 + 0.1225 = 1.3225
0.1225 + -0.7x + x2 = 1.3225

Factor a perfect square on the left side:
(x + -0.35)(x + -0.35) = 1.3225

Calculate the square root of the right side: 1.15

Break this problem into two subproblems by setting 
(x + -0.35) equal to 1.15 and -1.15.

Subproblem 1
x + -0.35 = 1.15

Simplifying
x + -0.35 = 1.15

Reorder the terms:
-0.35 + x = 1.15

Solving
-0.35 + x = 1.15

Solving for variable 'x'.

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

Add '0.35' to each side of the equation.
-0.35 + 0.35 + x = 1.15 + 0.35

Combine like terms: -0.35 + 0.35 = 0.00
0.00 + x = 1.15 + 0.35
x = 1.15 + 0.35

Combine like terms: 1.15 + 0.35 = 1.5
x = 1.5

Simplifying
x = 1.5

Subproblem 2
x + -0.35 = -1.15

Simplifying
x + -0.35 = -1.15

Reorder the terms:
-0.35 + x = -1.15

Solving
-0.35 + x = -1.15

Solving for variable 'x'.

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

Add '0.35' to each side of the equation.
-0.35 + 0.35 + x = -1.15 + 0.35

Combine like terms: -0.35 + 0.35 = 0.00
0.00 + x = -1.15 + 0.35
x = -1.15 + 0.35

Combine like terms: -1.15 + 0.35 = -0.8
x = -0.8

Simplifying
x = -0.8

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {1.5, -0.8}