Answer:
6 chickens, 11 cows.
Step-by-step explanation:
x - chickens
y - cows
x + y = 17
2x + 4y = 56 <-- chickens have 2 legs, cows have 4.
y = -x + 17
Substitute (-x+17) for y in the second equation.
2x + 4(-x + 17) = 56
2x -4x + 68 = 56
2x = 12
x = 6 chickens
Now substitute 6 for x
6 + y = 17
y = 11 cows
