Hello!
The answer is z = 16..
Solve it like this..
#1) Regroup terms
-3 = -7+z/4 ---> -3 = z/4 - 7
#2) Add 7 to both sides.
-3 = z/4 - 7 ---> -3 + 7 = z/4
#3) Do the addition.
-3 + 7 = z/4 ---> 4 = z/4
#4) Multiply both sides by 4.
4 = z/4 ---> 4 * 4 = z.
#5) Do the multiplication.
4 * 4 = z ---> 16 = z
Hope this helps! ☺♥