1. 2x + 1 = x + 11
subtract x from both sides
2x - x + 1 = x - x + 11
x + 1 = 11
subtract 1 form both sides
x + 1 - 1 = 11 -1
x = 10
2. a + 2 = 5 + 4a
subtract a from both sides
a - a + 2 = 5 + 4a - a
2 = 5 + 3a
subtract 5 from both sides
2 - 5 = 5 - 5 + 3a
3a = -3
divide both sides by 3
a = -1