We know bunnies have 4 legs. Let’s use the equation 4a, a being the number of bunnies and 4 being the number of legs each
Birds have 2 legs. let’s use the equation 2b.
There are 21 animals.
4a + 2b = 76, and a+b = 21
if u divide 76 by 4 you get 19.
however, you need 21 animals so you can replace 2 of them so
4 x 17 (19-2) and replace the eight legs with 4 birds
17 bunnies and 4 birds equals
68 + 8 = 76 legs and
17 + 4 = 21 animals