Question 972113
Take the first derivative:
(x-2) (1/2)*(x2+9)^(-1/2)*2x  +  (x^2+9)^1/2                First * derivative of second + second*derivative of first

(1/2)*2x=x
(x-2){(x^2+9)^(-1/2)} + (x^2+9)^(1/2)

x=4

2*25(-1/2) + 25^(1/2)

(2/5) + 5= 27/5

Now find function at x=4
2*sqrt(25)=10

point slope formula with slope 27/5  and point (4,10)

y-10= (27/5)(x-4)
y-10=(27/5)*x  - (108/5)
y= (27/5) x -58/5

{{{ graph (300,300,-20,20,-20,20,(x-2)*sqrt(x^2+9),(27/5)x-(58/5))}}}