Question

[Nguyễn Hoàng Khánh]

Bài 1: tìm phân số a/b 

a, a/b + 5/6 = 7/8

b, a/b ×2/3 = 3/4

c, 5/8 -a/b = 5/12

d, 5/8 + a/b = 13/8

Answer 1

[Huỳnh Quang Sang]

a) Ta có : \(\frac{a}{b}+\frac{5}{6}=\frac{7}{8}\)=> \(\frac{a}{b}=\frac{7}{8}-\frac{5}{6}\)

=> \(\frac{a}{b}=\frac{21}{24}-\frac{20}{24}=\frac{1}{24}\)

Vậy \(\frac{a}{b}=\frac{1}{24}\)

b) \(\frac{a}{b}\times\frac{2}{3}=\frac{3}{4}\)

=> \(\frac{a}{b}=\frac{3}{4}:\frac{2}{3}=\frac{3}{4}\times\frac{3}{2}=\frac{9}{8}\)

Vậy \(\frac{a}{b}=\frac{9}{8}\)

c) \(\frac{5}{8}-\frac{a}{b}=\frac{5}{12}\)

=> \(\frac{a}{b}=\frac{5}{8}-\frac{5}{12}=\frac{15}{24}-\frac{10}{24}=\frac{5}{24}\)

Vậy \(\frac{a}{b}=\frac{5}{24}\)

d) \(\frac{5}{8}+\frac{a}{b}=\frac{13}{8}\)

=> \(\frac{a}{b}=\frac{13}{8}-\frac{5}{8}=\frac{8}{8}=1\)

Vậy : ....