a - 4 + 7a + 11 Rearrange the expression and put like terms next to each other
a + 7a - 4 + 11 Combine like terms (a and 7a) (-4 and 11)*
8a + 7
* If it helps to combine a negative and positive number, you can switch them! -4 + 11 is the same as 11 - 4.
Just be sure to keep the signs with the right number.