0.3+(0.2a-0.5)+(a+2)=1.3

Solution for 0.3+(0.2a-0.5)+(a+2)=1.3 equation:

Simplifying
0.3 + (0.2a + -0.5) + (a + 2) = 1.3

Reorder the terms:
0.3 + (-0.5 + 0.2a) + (a + 2) = 1.3

Remove parenthesis around (-0.5 + 0.2a)
0.3 + -0.5 + 0.2a + (a + 2) = 1.3

Reorder the terms:
0.3 + -0.5 + 0.2a + (2 + a) = 1.3

Remove parenthesis around (2 + a)
0.3 + -0.5 + 0.2a + 2 + a = 1.3

Reorder the terms:
0.3 + -0.5 + 2 + 0.2a + a = 1.3

Combine like terms: 0.3 + -0.5 = -0.2
-0.2 + 2 + 0.2a + a = 1.3

Combine like terms: -0.2 + 2 = 1.8
1.8 + 0.2a + a = 1.3

Combine like terms: 0.2a + a = 1.2a
1.8 + 1.2a = 1.3

Solving
1.8 + 1.2a = 1.3

Solving for variable 'a'.

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

Add '-1.8' to each side of the equation.
1.8 + -1.8 + 1.2a = 1.3 + -1.8

Combine like terms: 1.8 + -1.8 = 0.0
0.0 + 1.2a = 1.3 + -1.8
1.2a = 1.3 + -1.8

Combine like terms: 1.3 + -1.8 = -0.5
1.2a = -0.5

Divide each side by '1.2'.
a = -0.4166666667

Simplifying
a = -0.4166666667