The line through the points (h, 3) and (4, 1) intersects the line `7x-9y-19=0` at right angle. Find the value of A.

Explanation

Slope of line passing through the points `(h,3)` and `(4,1)` is :
`m_(1)=(3-1)/(h-4)=(2)/(h-4)`
Given equation : `7x-9y-19=0`
Its slope `m_(2)=-(7)/(-9)=(7)/(9)`
Both lines are perpendicular.
`:. M_(1)m_(2)=-1`
`implies (2)/(h-4)*(7)/(9)=-1`
`implies h-4=(-14)/(9)`
`impliesh-(-14)/(9)+4=(22)/(9)`