5(m+1.8)(m-0.8)=0

Solution for 5(m+1.8)(m-0.8)=0 equation:

Simplifying
5(m + 1.8)(m + -0.8) = 0

Reorder the terms:
5(1.8 + m)(m + -0.8) = 0

Reorder the terms:
5(1.8 + m)(-0.8 + m) = 0

Multiply (1.8 + m) * (-0.8 + m)
5(1.8(-0.8 + m) + m(-0.8 + m)) = 0
5((-0.8 * 1.8 + m * 1.8) + m(-0.8 + m)) = 0
5((-1.44 + 1.8m) + m(-0.8 + m)) = 0
5(-1.44 + 1.8m + (-0.8 * m + m * m)) = 0
5(-1.44 + 1.8m + (-0.8m + m2)) = 0

Combine like terms: 1.8m + -0.8m = 1m
5(-1.44 + 1m + m2) = 0
(-1.44 * 5 + 1m * 5 + m2 * 5) = 0
(-7.2 + 5m + 5m2) = 0

Solving
-7.2 + 5m + 5m2 = 0

Solving for variable 'm'.

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

Divide each side by '5'.
-1.44 + m + m2 = 0

Move the constant term to the right:

Add '1.44' to each side of the equation.
-1.44 + m + 1.44 + m2 = 0 + 1.44

Reorder the terms:
-1.44 + 1.44 + m + m2 = 0 + 1.44

Combine like terms: -1.44 + 1.44 = 0.00
0.00 + m + m2 = 0 + 1.44
m + m2 = 0 + 1.44

Combine like terms: 0 + 1.44 = 1.44
m + m2 = 1.44

The m term is m.  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 + m2 = 1.44 + 0.25

Combine like terms:  + 0.25 = 1.25
1.25 + m2 = 1.44 + 0.25

Combine like terms: 1.44 + 0.25 = 1.69
1.25 + m2 = 1.69

Factor a perfect square on the left side:
(m + 0.5)(m + 0.5) = 1.69

Calculate the square root of the right side: 1.3

Break this problem into two subproblems by setting 
(m + 0.5) equal to 1.3 and -1.3.

Subproblem 1
m + 0.5 = 1.3

Simplifying
m + 0.5 = 1.3

Reorder the terms:
0.5 + m = 1.3

Solving
0.5 + m = 1.3

Solving for variable 'm'.

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

Add '-0.5' to each side of the equation.
0.5 + -0.5 + m = 1.3 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + m = 1.3 + -0.5
m = 1.3 + -0.5

Combine like terms: 1.3 + -0.5 = 0.8
m = 0.8

Simplifying
m = 0.8

Subproblem 2
m + 0.5 = -1.3

Simplifying
m + 0.5 = -1.3

Reorder the terms:
0.5 + m = -1.3

Solving
0.5 + m = -1.3

Solving for variable 'm'.

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

Add '-0.5' to each side of the equation.
0.5 + -0.5 + m = -1.3 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + m = -1.3 + -0.5
m = -1.3 + -0.5

Combine like terms: -1.3 + -0.5 = -1.8
m = -1.8

Simplifying
m = -1.8

Solution
The solution to the problem is based on the solutions
from the subproblems.
m = {0.8, -1.8}