Use properties of operations to determine whether the expressions are equivalent.
19) 7m + 10 + 9m and 16m + 10
20) 2b × 5 and 7b
21) 9 × (4r – 6) and 36r – 54
22) 12 + 5(2 + y) and 5y + 22
23) 15j + 11 – 6j and 9j + 11
24) 8(3x + 1) and 24x + 1

19. 7m + 10 + 9m = 16m + 10
      7m + 9m + 10 = 16m + 10
             16m + 10 = 16m + 10

20. 2b × 5 = 7b
          10b ≠ 7b

21. 9(4r - 6) = 36r - 54
  9(4r) - 9(6) = 36r - 54
     36r - 54 = 36r = 54

22. 12 + 5(2 + y) = 5y + 22
      12 + 5(2) + 5(y) = 5y + 22
      12 + 10 + 5y = 5y + 22
              22 + 5y = 5y + 22

23. 15j + 11 - 6j = 9j + 11
      15j - 6j + 11 = 9j + 11
              9j + 11 = 9j + 11

24. 8(3x + 1) = 24x + 1
  8(3x) + 8(1) = 24x + 1
        24x + 8 ≠ 24x + 1
          

C. expression because any expression or equation may contain more than one variable