Set 4: Linear Equations

Choice A is correct. Choice A is the correct answer. We model this with $20x + 50 = 170$, where $x$ is months. 1. Set up equation: $20x + 50 = 170$ 2. Subtract 50 from both sides: $20x = 170 - 50$ 3. Simplify: $20x = 120$ 4. Divide both sides by 20: $x = \frac{120}{20}$ 5. Simplify: $x = 6$ 6. Verify: $20(6) + 50 = 120 + 50 = 170$ ✓ So, you have been a member for 6 months. Choice B is incorrect because this results from adding 50 to 170: $220$, then $220 /20 = 11$. You subtract the joining fee. Choice C is incorrect because this is the cost of the monthly fees ($120), not the number of months. Choice D is incorrect because this results from dividing the total by the rate:$170 /20 = 8.5$. This ignores the joining fee.