Simplify x/(x+3)+(17x)/(3x+9)

$\frac{x}{x + 3} + \frac{17 x}{3 x + 9}$

Factor $3$ out of $3 x + 9$ .

Factor $3$ out of $3 x$ .

$\frac{x}{x + 3} + \frac{17 x}{3 (x) + 9}$

Factor $3$ out of $9$ .

$\frac{x}{x + 3} + \frac{17 x}{3 x + 3 \cdot 3}$

Factor $3$ out of $3 x + 3 \cdot 3$ .

$\frac{x}{x + 3} + \frac{17 x}{3 (x + 3)}$

To write $\frac{x}{x + 3}$ as a fraction with a common denominator, multiply by $\frac{3}{3}$ .

$\frac{x}{x + 3} \cdot \frac{3}{3} + \frac{17 x}{3 (x + 3)}$

Write each expression with a common denominator of $(x + 3) \cdot 3$ , by multiplying each by an appropriate factor of $1$ .

Multiply $\frac{x}{x + 3}$ by $\frac{3}{3}$ .

$\frac{x \cdot 3}{(x + 3) \cdot 3} + \frac{17 x}{3 (x + 3)}$

Reorder the factors of $(x + 3) \cdot 3$ .

$\frac{x \cdot 3}{3 (x + 3)} + \frac{17 x}{3 (x + 3)}$

Combine the numerators over the common denominator.

$\frac{x \cdot 3 + 17 x}{3 (x + 3)}$

Simplify the numerator.

Move $3$ to the left of $x$ .

$\frac{3 \cdot x + 17 x}{3 (x + 3)}$

Add $3 x$ and $17 x$ .

$\frac{20 x}{3 (x + 3)}$