Four friends are working to solve the system of inequalities y>5x and x≥9. Izabella substitutes 9 for x and then concludes that y≥45, but her friends disagree. Each friend presents an argument to explain his or her reasoning. Part A: Whose argument is correct? Part B: What is the correct solution? Select one answer for Part A and one answer for Part B. A: Ellis argues that because a solution must satisfy both equations, Izabella’s conclusion is incorrect. For example, if x=9, y must be greater than 5x, or 45. Thus, y≥45 cannot be the solution.
A: Maud argues that Izabella made a mistake in her substitution. She should have substituted 9 for y. This would give her 95>x. Thus, y≥45 cannot be the solution.
B: y≥45
A: Izabella’s argument is, in fact, correct.
B: x<95
A: Greyson argues that substitution is not a valid solution method for this problem. He claims that the only way to solve this problem is to graph it. Thus, y≥45 cannot be the solution.
B: y>45
B: The solution cannot be determined.