slopes of parallel lines

Question

In Algebra 1 I am given the following problem:

 

The slope of a line parallel to x + 3y = 63 equals what?

Please help me.

Answer 1

If two lines are parallel, they have the same slope.  Find the slope of the given line.

 

x + 3y = 63

y = (63 - x)/3

y = (-1/3)x + 21

 

The slope is -1/3, so any line in the xy plane with a slope of -1/3 is parallel to the given line.