2.5=-a+2a-3

Solution for 2.5=-a+2a-3 equation:

Simplifying
2.5 = -1a + 2a + -3

Reorder the terms:
2.5 = -3 + -1a + 2a

Combine like terms: -1a + 2a = 1a
2.5 = -3 + 1a

Solving
2.5 = -3 + 1a

Solving for variable 'a'.

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

Add '-1a' to each side of the equation.
2.5 + -1a = -3 + 1a + -1a

Combine like terms: 1a + -1a = 0
2.5 + -1a = -3 + 0
2.5 + -1a = -3

Add '-2.5' to each side of the equation.
2.5 + -2.5 + -1a = -3 + -2.5

Combine like terms: 2.5 + -2.5 = 0.0
0.0 + -1a = -3 + -2.5
-1a = -3 + -2.5

Combine like terms: -3 + -2.5 = -5.5
-1a = -5.5

Divide each side by '-1'.
a = 5.5

Simplifying
a = 5.5