Im writing a formal lab report and I need to explain how we ended up with x ( which was where the 5 is in the formula and our answer was 4.78) I can't remember how we got there and I need to explain it in the lab. Thanks.

the mass of empty evaporating dish was 40.892g mass of the hydrated compound was 2.994g mass of evaporating dish and CuSO4 anhydrous was 42.836g.