\(\dfrac{5\cdot6+5\cdot7}{5\cdot8+20}=\dfrac{5\cdot6+5\cdot7}{5\cdot4\cdot2+5\cdot4}=\dfrac{5\cdot\left(6+7\right)}{5\cdot4\cdot\left(2+1\right)}=\dfrac{5\cdot13}{5\cdot4\cdot3}=\dfrac{13}{4\cdot3}=\dfrac{13}{12}\)
\(\dfrac{5.6+5.7}{5.8+20}\)
=\(\dfrac{5.\left(6+7\right)}{5.\left(8+4\right)}\)
=\(\dfrac{5.13}{5.12}\)
=\(\dfrac{13}{12}\)