There is an animal farm where chickens and cows live. all together, there are 84 heads and 210 legs. how many chickens and cows are there on the farm?

1 Chicken have = 2 legs

1 Cow have = 4 legs

No of cows = x

No of chickens = y

Total no of legs = 4x + 2y = 210(1)

Total No of heads = x + y = 84(2)

x = 84 - y( from (2) )

Substituting the above equation in (1)

4 ( 84 - y) + 2y = 210

336 - 4y + 2y = 210

336 - 2y = 210

-2y = -126

= y = 63

No of cows = 84-63 = 21

∴ Total no of cows = 21

Total no of chickens = 63

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18