which equation represents a line which is parallel to the line x-3y=15?

Step-by-step explanation:
Two lines that are parallel have the same slope. If we make [tex]x - 3y = 15[/tex] in to slope-intercept form it'll be like this:
[tex]x - 3y = 15 \\ -3y = 15 - x \\ y = \frac{15 - x}{-3} \\ y = \frac{1}{3}x - 5[/tex]
Now we know [tex]y = \frac{1}{3}x - 5\\[/tex] as its slope-intercept form we can see the slope is [tex]\frac{1} {3}\\[/tex].
[tex]y = \frac{1}{3}x + 4\\[/tex] has the same slope as [tex]y = \frac{1}{3}x - 5\\[/tex] so they are both parallel.
[tex]y = \frac{1}{3}x + 4\\[/tex]