Set 6: Systems of Equations (Intermediate)

Choice A is correct. Choice A is the correct answer. Since $y = 2 x - 7$ is already isolated, substitute directly into the second equation. Step 1: Substitute $y = 2 x - 7$ into $4x - 3 y = 5$: $$$4x - 3(2 x - 7) = 54x - 6 x + 21 = 5$-2 x + 21 = 5-2 x = -16x = 8 Step 2: Find $y$: $y = 2(8) - 7 = 16 - 7 = 9$ Solution: $(8, 9)$ Verification: $4(8) - 3(9) = 32 - 27 = 5$ ✓ Strategic Tip: When y is isolated, substitution eliminates the need for algebraic manipulation of the first equation. Choice B is incorrect because $4(5) - 3(3) = 20 - 9 = 11 \neq 5$. Choice C is incorrect because $4(7) - 3(7) = 28 - 21 = 7 \neq 5$. Choice D is incorrect because $4(6) - 3(5) = 24 - 15 = 9 \neq 5$.