Final answer:
The lines -2x + 8y = 9 and x - 4y = 21 are parallel.
Step-by-step explanation:
The given equations are -2x + 8y = 9 and x - 4y = 21. To determine whether the lines are parallel, perpendicular, or neither, we need to analyze their slopes. Rewrite the equations into slope-intercept form, y = mx + b. Equation 1 becomes y = (1/4)x - (21/4), and Equation 2 becomes y = (1/4)x + (9/8). From the equations, we can see that the slopes of both lines are equal, which means the lines are parallel to each other.