a. Find Y if the point (-6,y) is on the line that passes through (-1,7) and (3,-2).
b. A line has a slope of -(3/7) and its y-intercept is (0,18). What is its x-intercept?
c. The distance between the points (x,21) and (4,7) is 10sqrt2 Find the sum of all possible values of x.