x/r - h = 4 for x

[math_celebrity]

x/r - h = 4 for x

Add h to each side:
x/r - h + h = h + 4

Cancel the h's on the left side, we get:
x/r = h + 4

Multiply each side by r to isolate x:
xr/r = r(h + 4)

Cancel the r's on the left side, we get:
x = r(h + 4)