Question

[Lã Kim Ngân]

*: So sánh hai phân số A và B biết

a - (6/15 + 3/15) x 4/9 = 5/9

(b + 7/8) x 36/14 = 15/4

Answer 1

[Akai Haruma]

Lời giải:

$a-(\frac{6}{15}+\frac{3}{15})\times \frac{4}{9}=\frac{5}{9}$

$a-\frac{9}{15}\times \frac{4}{9}=\frac{5}{9}$

$a-\frac{4}{15}=\frac{5}{9}$

$a=\frac{5}{9}+\frac{4}{15}=\frac{37}{45}$

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$(b+\frac{7}{8})\times \frac{36}{14}=\frac{15}{4}$

$b+\frac{7}{8}=\frac{15}{4}:\frac{36}{14}$

$b+\frac{7}{8}=\frac{35}{24}$

$b=\frac{35}{24}-\frac{7}{8}=\frac{7}{12}$

Ta thấy: $\frac{7}{12}=\frac{35}{60}< \frac{37}{60}< \frac{37}{45}$

Suy ra $b< a$