Four equations are listed below:
(a) y=−5x4 (b) y=21x4 (c) y=−3x3 (d) y=2x3
Descriptions of four unlabeled curves are given:
A. U-shaped curve opening upward, symmetric about the y-axis.
B. U-shaped curve opening downward, symmetric about the y-axis.
C. S-shaped curve increasing as x moves from left to right, symmetric about the origin.
D. S-shaped curve decreasing as x moves from left to right, symmetric about the origin.
Match each equation with the correct description and provide suitable justification.
a. (i) Write the letter (A–D) that matches each equation (a–d).
b. (ii) Justify every match by referring to the degree and the sign of the leading coefficient of the corresponding equation.