bill and ron build towers using blocks. the expression 4b + 2 represents the number of blocks bill uses. the expression 8b – 5 represents the number of blocks ron uses.

complete the expression to represent the total number of blocks bill and ron use.

__ b - __

They use 9 blocks each, a total of 18 blocks.

Bill: 4b + 2      b = 1.75 ; then, 4(1.75) + 2 = 7 + 2 = 9
Ron: 8b - 5      b = 1.75; then, 8(1.75) -5 = 14 - 5 = 9

To look for the value of b; I assume that both used the same number of blocks.

4b + 2 = 8b - 5
4b - 8b = -5 -2
-4b = -7
-4b/-4 = -7/-4
b = 1.75