Whats the slope and y-intercept sorry i keep getting it wrong

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

65 8 7 4 5 6 8 4 3 2 1 9 5 6 4 2 1 6 5 1 5 1 3 2 3 5 multiply the third number in the first row by the seventh number in the third row. add this result to the fifth number in the second row. add to this total ten times the fourth number in the third row. subtract the eighth number in the first row from the result.

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=