Set 15: Linear Equations

Choice B is correct. Choice C is the correct answer. 1. Start with the equation: $7x - 21 = 14$ 2. Add 21 to both sides: $7x = 14 + 21$ 3. Simplify: $7x = 35$ 4. Divide both sides by 7: $x = \frac{35}{7}$ 5. Simplify: $x = 5$ 6. Verify: $7(5) - 21 = 35 - 21 = 14$ ✓ Choice B is incorrect because this results from subtracting 21 from 14: $-7$, then $-7/7 = -1$. We must add to undo subtraction. Choice D is incorrect because this is the value of $7x$. Don't stop early! Choice A is incorrect because this results from multiplying 35 by 7: $245$.