中等MATH-FUNC-005
Which description matches y = −2(x − 1)^2 + 4?
A. Opens upwards, vertex (1, 4)
B. Opens downwards, vertex (1, 4)✓ 答案
C. Opens downwards, vertex (−1, 4)
D. Opens upwards, vertex (−1, −4)
解說
The coefficient −2 is negative, so the parabola opens downwards. The vertex of −2(x − 1)^2 + 4 is (1, 4).