What set does not contain -3​

If f(x)=x+7 and g(x)=1/x what is (fog)(x)

Avery’s piggy bank has 300 nickels, 450 pennies, and 150 dimes. she randomly picks three coins. each time she picks a coin, she makes a note of it and puts it back into the piggy bank before picking the next coin.

If you prove that ∆wxz is congruent to ∆yzx, which general statement best describes what you have proved?