Choice B is the correct answer. Since y=x+7 is already isolated, we can substitute it into the second equation.
Step 1: Substitute y=x+7 into 3x−2y=−8:
3x−2(x+7)=−83x−2x−14=−8x−14=−8x=6
Step 2: Find y using y=x+7:
y=6+7=13
Solution: (6,13)
Verification: 3(6)−2(13)=18−26=−8 ✓
💡 Strategic Tip: When one equation is already solved for a variable, substitution is the most efficient method.
Choice A is incorrect because3(4)−2(11)=12−22=−10 eq−8.
Choice C is incorrect because3(2)−2(9)=6−18=−12 eq−8.
Choice D is incorrect because3(5)−2(12)=15−24=−9 eq−8.