Question

Tính nhanh

\(\frac{0,75+\frac{3}{7}+\frac{3}{11}}{2\frac{1}{4}+\frac{9}{11}+\frac{9}{7}}\)

Answer 1

Đặt tử = A.Ta có: 

\(A=0,75+\frac{3}{7}+\frac{3}{11}=\frac{3}{4}+\frac{3}{7}+\frac{3}{11}\)

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

Đặt mẫu = B.Ta có:

\(B=2\frac{1}{4}+\frac{9}{11}+\frac{9}{7}=\frac{9}{4}+\frac{9}{11}+\frac{9}{7}\)

\(=9\left(\frac{1}{4}+\frac{1}{11}+\frac{1}{7}\right)\)

Thay A và B vào ta đc: \(\frac{A}{B}=\frac{3\left(\frac{1}{4}+\frac{1}{7}+\frac{1}{11}\right)}{9\left(\frac{1}{4}+\frac{1}{11}+\frac{1}{7}\right)}=\frac{3}{9}=\frac{1}{3}\)