Algebra practice question

Answer: 6

At the intersection both equations give the same y, so 2x − 3 = −x + 6. Then 3x = 9 and x = 3. Substitute into either line: y = 2(3) − 3 = 3. The point is (3, 3), so a + b = 6.

Common wrong answers

If you answered 0

0 would mean a = −b. Both coordinates are 3, so the sum is positive.

If you answered 3

3 is the x-coordinate (and also the y-coordinate). The question asks for their SUM, 3 + 3 = 6.

If you answered 9

9 is 3x from the step 3x = 9. Divide by 3 to get x = 3, then find y and add.

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