A parabola with a vertex at (0, 0) has a directrix that crosses the negative part of the y-axis. Which could be the equation of the parabola?

A. x² = -4y
B. x² = 4y
C. y2 = 4x
D. y2 = -4x

What is an equation of the line that passes through the point (-2,3) and is parallel to the line whose equations is y=3/2x-4? i am stuck between y=3/2x or y=3/2x+6 : (

Refer to interactive solution 17.45 to review a method by which this problem can be solved. the fundamental frequencies of two air columns are the same. column a is open at both ends, while column b is open at only one end. the length of column a is 0.504 m. what is the length of column b?

A. 90 degrees b. 45 degrees c. 30 degrees d. 120 degrees