How Can I Use Substitution to Solve This Integral?

[karush]

$$\int\frac{2x}{x^2+9}\ \text{dx}$$
I thot I could use
$$u={x}^{2}+9$$
But counldn't go thru with it

 

[evinda]

$$\int\frac{2x}{x^2+9}\ \text{dx}$$
I thot I could use
$$u={x}^{2}+9$$
But counldn't go thru with it

(Wave)

$$u=x^2+9 \Rightarrow du=2x dx $$

$$\int\frac{2x}{x^2+9} dx=\int \frac{du}{u}=\ln |u|+c=\ln |x^2+9|+c=\ln(x^2+9)+c$$