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