-(a+3)=2(m+1)-7

Solution for -(a+3)=2(m+1)-7 equation:

Simplifying
-1(a + 3) = 2(m + 1) + -7

Reorder the terms:
-1(3 + a) = 2(m + 1) + -7
(3 * -1 + a * -1) = 2(m + 1) + -7
(-3 + -1a) = 2(m + 1) + -7

Reorder the terms:
-3 + -1a = 2(1 + m) + -7
-3 + -1a = (1 * 2 + m * 2) + -7
-3 + -1a = (2 + 2m) + -7

Reorder the terms:
-3 + -1a = 2 + -7 + 2m

Combine like terms: 2 + -7 = -5
-3 + -1a = -5 + 2m

Solving
-3 + -1a = -5 + 2m

Solving for variable 'a'.

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

Add '3' to each side of the equation.
-3 + 3 + -1a = -5 + 3 + 2m

Combine like terms: -3 + 3 = 0
0 + -1a = -5 + 3 + 2m
-1a = -5 + 3 + 2m

Combine like terms: -5 + 3 = -2
-1a = -2 + 2m

Divide each side by '-1'.
a = 2 + -2m

Simplifying
a = 2 + -2m