B. Mark bought 4 packs of gum for $1.5 each. 6 dollars in total. The 4 packs of gum is on the x axis (x, y) and the the total is 6 dollars.
Let x represent the cost of book B
Book A: $17.50
Book B: x
Sales tax: (A + B) x 6% = .06(17.50 + x) = 1.05 + .06x
book A + book B + sales tax = total cost
(17.50) + (x) + (1.05 + .06x) = 44.52 <em>plugged in all of the values</em>
18.55 + 1.06x = 44.52 <em>added like terms</em>
1.06x = 25.97 <em>subtracted 18.55 from both sides</em>
x = 24.50 divided 1.06 from both sides
Answer: $24.50
V + 160 = 11
v = -149
Hope this helps