Daryl wants to buy a science book and a math book. The cost of a science book is $8 more than the cost of a math book. The cost of 9 math books is the same as the cost of 7 science books. What is the cost of each book?

Analyze the solution below. 7 3 x = −2 7 3 x(3 7 ) = −2(3 7 ) x = − 6 7 what property was used to solve the equation? property of opposites division property of equality addition property of equality multiplication property of equality