There are 56 treats to be given to 10 pets. some of those are cats, others are dogs. cats take 5 biscuits, dogs take 6. how many cats & dogs are there?

Your equations would be

c+d=10
5c+6d=56     (c= # of cats, d= # of dogs)  Then solve

I am using elimination and multiply the first equation by -5

-5c-5d=-50
5c+6d=56

Then eliminate

-d=-6   Divide by -1   d=6

Then solve for c

c+6=10
c=4

Hope this helps!