Question 1019792
If {{{y = 3sqrt(x)}}}, then the derivative is the function {{{dy/dx=3/(2sqrt(x))}}}
==> when x = 4, {{{dy/dx = 3/4}}}, which is the slope of the line tangent at the point (4,6) of the curve.

==> {{{y - 6 = (3/4)(x-4)}}}
<==> 4y - 24 = 3x - 12
<==> 3x - 4y +12 = 0 is the tangent line.

For x = 9, the procedure is the same.