Question

tính nhanh: 1x3x5+2x6x10+4x12x20+7x21x35

                  ____________________________

                 1x5x7+2x10x14+4x20x28+7x35x49

ai giúp em với ạ

Answer 1

\(\frac{1.3.5+2.6.10+4.12.20+7.21.35}{1.5.7+2.10.14+4.20.28+7.35.49}=\frac{3.5+\left(4.12.4\right)5+\left(2.6.2\right).5+\left(7.21.7\right).5}{5.7+\left(2.2.14\right).5+\left(4.4.28\right).5+\left(7.7.49\right).5}\)

Answer 2

mk gợi ý thôi bạn tự làm tiếp