what’s 6/7 - 1/2? also how do i subtract fractions with unlike denominators? you don’t have to answer the 2nd question

Could answer every question with steps

An animal shelter has 21 puppies. if the puppies are 28% of the total dog and cat population , how many dogs and cats are in the animal shelter

Suppose y varies directly with x. write a direct variation equation that relates x and y. then find the value of y when x=12 y=7 when x=3