3a+11=7a-13 with shown work

3a+11=7a-13

move 7a to the other side

sign changes from + 7a to - 7a

3a-7a+11 = 7a-7a-13 (combine like terms)

3a-7a+11 = - 13

-4a+11 = - 13

move 11 to the other side

sign changes from + 11 to - 11

-4a+11-11 = - 13-11

-4a = - 13-11

-4a = - 24

divide both sides by - 4 to get a by itself

-4a/-4 = - 24/-4

Answer: a = 6