$$\frac { x ^ { 2 } + 4 x + 3 } { x ^ { 2 } + 6 x + 8 }$$
$\frac{\left(x+1\right)\left(x+3\right)}{\left(x+2\right)\left(x+4\right)}$
$\frac{x^{2}+4x+3}{x^{2}+6x+8}$
