3a-42=(a+4)

Solution for 3a-42=(a+4) equation:

Simplifying
3a + -42 = (a + 4)

Reorder the terms:
-42 + 3a = (a + 4)

Reorder the terms:
-42 + 3a = (4 + a)

Remove parenthesis around (4 + a)
-42 + 3a = 4 + a

Solving
-42 + 3a = 4 + a

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.
-42 + 3a + -1a = 4 + a + -1a

Combine like terms: 3a + -1a = 2a
-42 + 2a = 4 + a + -1a

Combine like terms: a + -1a = 0
-42 + 2a = 4 + 0
-42 + 2a = 4

Add '42' to each side of the equation.
-42 + 42 + 2a = 4 + 42

Combine like terms: -42 + 42 = 0
0 + 2a = 4 + 42
2a = 4 + 42

Combine like terms: 4 + 42 = 46
2a = 46

Divide each side by '2'.
a = 23

Simplifying
a = 23