Explain pls I have to know how to do this in a few hours !!

Factor the expression using the gcf. the expression 21m−49n factored using the gcf

What are the domain and range of the function f(x)=2^x+1

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.