Can someone please help??

let the number of cows = x

let the number of chickens = y

since there are 42 heads:

x + y = 42

and since a cow has 4 legs, and a chicken has 2

4x + 2y = 144

from first equation:

x + y  = 42

x = 42 - y (now, we will substitute this in the second equation)

4(42 - y) + 2y = 144

168 - 4y + 2y  = 144

2y = 168 - 144

2y = 24

y = 12

now, we know the number of chickens. we will replace y with 12 in the first equation since it is more simpler

x + 12 = 42

x = 30

So, there are 30 cows and 12 chickens

it if you find the answer helpful

answer is b

step-by-step explanation: