Set 13: Linear Inequalities (Advanced)

Choice A is correct. Choice A is the correct answer. This standard two-step inequality follows a predictable solving pattern. 1. Add 12: $7x - 12 + 12 > 9 + 12$, giving $7x > 21$ 2. Divide by 7: $\frac{7 x}{7} > \frac{21}{7}$, giving $x > 3$ 3. Verify: Try $x = 4$: $7(4) - 12 = 28 - 12 = 16 > 9$ Strategic Tip: Keep operations organized: deal with constants first, then coefficients. Choice B is incorrect because it reverses the inequality without mathematical reason. Choice C is incorrect because it appears to confusingly divide 9 by -12 or similar, leading to an incorrect fraction. Choice D is incorrect because it represents the intermediate step $7x > 21$ without completing the division.