What operation will eliminate the x variable in -6+6y=6

Arestaurant chef made 1 1/2 jars of pasta sauce. each serving of pasta requires 1/2 of a jar of sauce. how many servings of pasta will the chef be able to prepare using the sauce?

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?