Set 4: Systems of Equations

Choice C is correct. Choice C is the correct answer. Multiply the second equation by 2 to eliminate $y$. Step 1: Multiply second by 2: $6x - 2 y = 16$ Step 2: Add to the first equation: (7 x + 2 y) + (6 x - 2 y) = 31 + 16$13x = 47$x = \frac{47}{13} Non-integer. - First: $7(3) + 2(5) = 21 + 10 = 31$ ✓ - Second: $3(3) - 5 = 9 - 5 = 4 \neq 8$ Strategic Tip: Multiplying by 2 creates $-2 y$ to cancel $+2 y$. Choice A is incorrect because $7(5) + 2(-2) = 31$ ✓, but $3(5) - (-2) = 17 \neq 4$. Choice B is incorrect. Choice D is incorrect.