math
posted by coby .
How many chickens and rabbits are in the yard if you have 18 heads and 58 feet

chickens have 2 feet. Rabbit have 4. They both each have 1 head. Let x be chickens and y be rabbits.
2(x + y = 18)
2x + 4y = 58
The subtract the equations from each other.
2x + 4y = 58
2x + 2y = 36

2y = 22
y = 11 so x = 7