SOLUTION
Line 1 is given as

let's find the equation of line 2, it passes through points (2, 3) and (4, 4)
The slope is

The slope of line 2 is 1/2
If the two lines are perpendicular, then the product of their slope will be = -1, that is

Since the product of their slope = -1
Hence Line 1 and Line 2 are perpendicular