Final answer:
The solution to the inequality involves multiplying both sides by -3.5 and reversing the inequality sign, which results in r < -31.85, which corresponds to option (a).
Step-by-step explanation:
To solve the inequality r/-3.5 > 9.1, we need to isolate the variable r on one side of the inequality. Multiplying both sides of the inequality by -3.5 and remembering to reverse the inequality sign when multiplying or dividing by a negative number, we get:
r < (-3.5) * 9.1
Solving this gives us a negative number:
r < -31.85
Therefore, the correct answer corresponds to option (a) r < -31.85.