I need the variables the equations and the solutions

Question

a farmer was counting his hens and cows hens have two legs each and cows have four legs each he countrd a total of 76 legs and 21 animals how mnay of each type if animal are there

Answer 1

2H + 4C = 76

H + C = 21

2H + 2C = 42

subtract last equation from the 1st

2C = 34

C = 17 cows

H=21-17 = 4 hens