$$\frac { 3 x + 1 } { 9 x ^ { 2 } + 3 x + 1 } + \frac { 3 x - 1 } { 9 x ^ { 2 } - 3 x + 1 } + \frac { 2 } { 81 x ^ { 4 } + 9 x ^ { 2 } + 1 }$$
Evaluate
$\frac{2\left(3x+1\right)}{9x^{2}+3x+1}$
Short Solution Steps
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $9x^{2}+3x+1$ and $9x^{2}-3x+1$ is $\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)$. Multiply $\frac{3x+1}{9x^{2}+3x+1}$ times $\frac{9x^{2}-3x+1}{9x^{2}-3x+1}$. Multiply $\frac{3x-1}{9x^{2}-3x+1}$ times $\frac{9x^{2}+3x+1}{9x^{2}+3x+1}$.
Since $\frac{\left(3x+1\right)\left(9x^{2}-3x+1\right)}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ and $\frac{\left(3x-1\right)\left(9x^{2}+3x+1\right)}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ have the same denominator, add them by adding their numerators.
Since $\frac{54x^{3}}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ and $\frac{2}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ have the same denominator, add them by adding their numerators.
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $9x^{2}+3x+1$ and $9x^{2}-3x+1$ is $\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)$. Multiply $\frac{3x+1}{9x^{2}+3x+1}$ times $\frac{9x^{2}-3x+1}{9x^{2}-3x+1}$. Multiply $\frac{3x-1}{9x^{2}-3x+1}$ times $\frac{9x^{2}+3x+1}{9x^{2}+3x+1}$.
Since $\frac{\left(3x+1\right)\left(9x^{2}-3x+1\right)}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ and $\frac{\left(3x-1\right)\left(9x^{2}+3x+1\right)}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ have the same denominator, add them by adding their numerators.
Since $\frac{54x^{3}}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ and $\frac{2}{\left(9x^{2}-3x+1\right)\left(9x^{2}+3x+1\right)}$ have the same denominator, add them by adding their numerators.