Question

(4,?) is on the line y = 2x 3

Answer 1

(4,?) is on the line y = 2x 3

The line y = 2x 3 is in slope-intercept form
2 = slope
3 = y intercept 

A line perpendicular to the line y = 2x 3 will have a slope of 1/2 which is the inverse reciprocal of 2

y = 1/2x + b

Use the point you want to go through to find 'b'

4 = 1/2(2) + b
4 = 1 + b
b = 5

y = 1/2x + 5

Answer = 2;(4,2) is on the line y = 2x 3