A = \(\frac{1.3.5+2.6.10+4.12.20+7.21.35}{1.5.7+2.10.14+4.20.28+7.35.49}\)
A = \(\frac{1.3.5.\left(1+8+64+343\right)}{1.5.7.\left(1+8+64+343\right)}\)
A = \(\frac{1.3.5}{1.5.7}\)
A = \(\frac{3}{7}=\frac{231}{539}\)
B = \(\frac{308}{708}=\frac{77}{177}=\frac{231}{531}\)
Vì \(\frac{231}{539}