The point

P$(5,3)$

lies on the curve

y $=3/(4$ x$).$

$($a$)$ If Q is the point

$($x$,3/(4$ x$)),$

use your calculator to find the slope

mPQ

of the secant line PQ $($correct to six decimal places$)$ for the following values of x$.$

$($i$)4\mathrm{.}9$

mPQ $=$