Which of the following equations best describes the figure above?
A. y = -x4 + 6
B. y = -(x2 + 6)
C. y = -x2 + 6
D. y = x4 + 6
Answer:B
Which of the following equations best describes the figure above?
A. y = -x4 + 6 B. y = -(x2 + 6) C. y = -x2 + 6 D. y = x4 + 6
Explanation: B The graph shown is a regular parabola that has been turned upside down and moved down 6. The equation of a regular parabola that points upward is y = x2. Therefore, the graph of a parabola that points downwards is y = -x2. Eliminate (D) because that answer is missing the negative sign. To move a parabola down 6 units, a 6 must be subtracted from the equation of the parabola. Eliminate (A) and (C), which add 6 instead. Choice (B) can be rewritten as y = -x2 - 6. The correct answer is (B).