Coordinates

The answer is (-3, -129)

Slope of first line = - 1/5    perpindicular is = 5

16x + py = q        slope =   -16/p = 5    p = - 16/5

16 x - 16/5 p = q       sub in the point (8,3) to find the value of Q = 118.4

We can write  the first line as

y  =  (-1/5)x + 23/5     Note that the slope  =  -1/5

If the second ine is perpendicular to this one, then it will have a slope of 5

So we have  that

16x + Py  = Q

Py = -16x + Q

y = (-16/P ) + Q/P

This  means  that    -16/P  = 5    so   P =  -16/5

And since   (8,3)  is on this line then

16 (8) + (-16/5)(3)  =Q

128 - 48/5  = Q

592/5  = Q

So   (P, Q)  = (-16/5, 592/5)

Because the lines are perpendicular, the other line has a slope of $5$.

This means that the equation is $y = 5x + b$

Plugging in the point (8, 3), we get: $3= 40+b$, meaning $b = -37$

Now, we have to convert $y = 5x - 37$ into standard form. 

Subtracting $5x$ from both sides, we get $-5x + y = -37$

Multiplying the equation by $-{16 \over 5}$ , we get: $16x-3.2y=118.4$

From here, we can find the pair to be $\color{brown}\boxed{(-3.2, 118.4)}$