Answer:
They are perpendicular!
Explanation:
Get 7x-3y=-21 into y=mx+b format.
7x-3y=-21 Bring 7x to the other side
-3y=7x-21 Divide -3 by both sides, it cancels out on the y's side.
y=-7/3x+7 Two negatives equal a positive, that it why 7 is positive.
y=-7/3x+7 is the line, the other is y=-3/7x+5
The slope of this line is -7/3 , the slope of the given line is -3/7.
Lines are perpendicular if the slopes are opposite reciprocals, such as this.
So, while they intercept at different points on the y-axis, they will intersect at some point! This makes them perpendicular.