algebra question

Question

The amount of acid used to neutralize a base is directly proportional to the amounts used. If 9g of hydrochloric acid neutralizes 10g of lye, how many grams of lye are neutralized by 72g of hydrochloric acid? (You do not need to answer in a complete sentence.)

Answer 1

9/10=72/x => x = 80

Answer 2

9g HCl + 10g lye

72g HCl + xg lye

72/9=8 so we have a factor of 8

therefore 10x8=80g of lye can be neutralized