You didn't give any choices, but the equation looks like this: 17 = 2x + 5. Solving that for x tells you that he went on a big water slide 6 times. 2 times 6 plus 5 is the $17 he spent at the park. See how well that works out?
Answer:
The completed reaction is
CaCO3 + 2 HCl → (Ca+2 + 2 Cl-)aq + H2O + CO2↑
X = 70 and y = 35, I hope this helps