15 - w/4 = 28.
Our goal is to find the variable by itself.
First, reverse the equation to cancel itself out.
Use the Multiplication and Addition Property of Equality.
So do +15 to cancel 15 out.
Add the 15 to 28, which equals 43.
Do x4, to cancel 4 out.
43 x 4 = 172.
w will equal 172.
15 - 172/4 = 28.