I assume you want to find the value of w
The first thing we will do is divide both sides by 0.25
4/0.25 = 0.25(w - 4.3)/0.25
The two 0.25s cancel each other. 4/0.25 = 16
16 = w - 4.3
Now we add 4.3 to both sides
16 + 4.3 = w - 4.3 + 4.3
The two 4.3s cancel each other 16 + 4.3 = 20.3
20.3 = w
w = 20.3