For which equation would x = 4 be a solution?

4 x + 7 = 23
4 x ÷ 8 = 8
8 - 5 x = 1
7 + 3 x = 18

At the "no mutants allowed" country farm, every sheep has 4 legs, every chicken has two legs, and all animals have only 1 head. asked to count how many sheep and chicken are in the fields, a farm boy reports back that there are 140 feet and 50 heads. how many sheep and chicken are there? there are sheep and chicken at the farm.