9=a+b+4

Solution for 9=a+b+4 equation:

Simplifying
9 = a + b + 4

Reorder the terms:
9 = 4 + a + b

Solving
9 = 4 + a + b

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.
9 + -1a = 4 + a + -1a + b

Combine like terms: a + -1a = 0
9 + -1a = 4 + 0 + b
9 + -1a = 4 + b

Add '-9' to each side of the equation.
9 + -9 + -1a = 4 + -9 + b

Combine like terms: 9 + -9 = 0
0 + -1a = 4 + -9 + b
-1a = 4 + -9 + b

Combine like terms: 4 + -9 = -5
-1a = -5 + b

Divide each side by '-1'.
a = 5 + -1b

Simplifying
a = 5 + -1b