If the line y = 2x is translated according to the vector a, and the line y = 2x + 6 is obtained, then the vector a () A. Only (- 3,0) B. only (0,6) C can only be (- 3,0) or (0,6) d The correct answer is D, but I chose B, which is not "in the same plane, any vector has only a unique representation." so this question should choose B?

If the line y = 2x is translated according to the vector a, and the line y = 2x + 6 is obtained, then the vector a () A. Only (- 3,0) B. only (0,6) C can only be (- 3,0) or (0,6) d The correct answer is D, but I chose B, which is not "in the same plane, any vector has only a unique representation." so this question should choose B?

Let (x, y) be on the straight line y = 2x, (x ', y') be on the straight line y = 2x + 6, and the vector a = (h, K), then: X '= x + H, y' = y + K: x = x '- H (1) y = y' - K (2) because y = 2x substitutes (1) (2), there is: y '- k = 2x' - 2h, that is, y '= 2x' - 2H + K (3) because y = 2x + 6, that is, y '= 2x' + 6, compared with (3), there is: - 2H + k = 6 (4) equation