The given equation is (6+y)h =C
First we move h to the right side and for that we divide both sides by h, that is
[tex] 6+y = \frac{C}{h} [/tex]
Now we need to get rid of 6 from the left side, and for that we subtract 6, that is
[tex] y=\frac{C}{h} -6 [/tex]
And that's the required answer .