4
algebra

What is the intersection point of the lines y=x+8y = -x + 8 and y=2x1y = 2x - 1?

A

(4,7)(4, 7)

B

(2,3)(2, 3)

C

(3,5)(3, 5)

D

(1,7)(1, 7)

Correct Answer: C

Choice C is the correct answer. To find the intersection, we set the two expressions for yy equal to each other.

Step 1: Set the equations equal: x+8=2x1-x + 8 = 2x - 1

Step 2: Solve for xx: 8+1=2x+x8 + 1 = 2x + x9=3x9 = 3xx=3x = 3

Step 3: Find yy using either equation (using the first): y=3+8=5y = -3 + 8 = 5

Solution: (3,5)(3, 5)

Verification: 5=2(3)1=61=55 = 2(3) - 1 = 6 - 1 = 5

💡 Strategic Tip: The intersection point satisfies both equations simultaneously.

Choice A is incorrect because7=4+8=47 = -4 + 8 = 4 .

Choice B is incorrect because3=2+8=6 eq33 = -2 + 8 = 6 \ eq 3.

Choice D is incorrect because7=1+8=77 = -1 + 8 = 7 ✓, but 7 eq2(1)1=17 \ eq 2(1) - 1 = 1.