Question

tính nhanh giá trị của biểu thức 

M = \(\frac{\frac{3}{5}+\frac{3}{7}-\frac{3}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{11}}\)

Answer 1

Ta có:3/5+3/7-3/11=3.(1/5+1/7-1/11)

4/5+4/7-4/11=4.(1/5+1/7-1/11)

=>M=[3.(1/5+1/7-1/11)]/[4.(1/5+1/7-1/11)]=3/4

Answer 2

M = \(\frac{\frac{3}{5}+\frac{3}{7}-\frac{3}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{11}}=\frac{3\left(\frac{1}{5}+\frac{3}{7}-\frac{3}{11}\right)}{4\left(\frac{1}{5}+\frac{1}{7}-\frac{1}{11}\right)}=\frac{3}{4}\)