\(\dfrac{7}{x+1}=\dfrac{7\left(x+2\right)}{\left(x+1\right)\left(x+2\right)}=\dfrac{7x+14}{\left(x+1\right)\left(x+2\right)}\)
\(\dfrac{14}{x+2}=\dfrac{14\left(x+1\right)}{\left(x+1\right)\left(x+2\right)}=\dfrac{14x+14}{\left(x+1\right)\left(x+2\right)}\)

