Use distributive property.
4(m - 2) = 24
Add 8 on both sides to leave the variable on one side.
4m - 8 = 24
+8 +8
Divide 4 on both sides.
4m = 32
---- ------
4 4
You'll get a solution of 8.
m = 8
Check:
4(8 - 2) = 24
32 - 8 = 24
24 = 24
