
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.



a: \(=\dfrac{2}{3}\cdot\dfrac{4}{5}\cdot\dfrac{5}{6}=\dfrac{2}{3}\cdot\dfrac{2}{3}=\dfrac{4}{9}\)
b: \(=\dfrac{5}{6}\cdot\dfrac{1}{5}=\dfrac{1}{6}\)

a. C1: \(\dfrac{8}{15}.\dfrac{5}{6}=\dfrac{4}{9}\)
C2: \(\dfrac{2}{3}.\dfrac{4}{5}.\dfrac{5}{6}=\dfrac{2.4.5}{3.5.3.2}\)
Triệt tiêu phần giống nhau ở tử và mẫu ta có
\(=\dfrac{4}{9}\)
b. \(C1:\left(\dfrac{1}{2}+\dfrac{1}{3}\right).\dfrac{1}{5}=\dfrac{5}{6}.\dfrac{1}{5}=\dfrac{1}{6}\)
C2: \(\dfrac{1}{2}.\dfrac{1}{5}+\dfrac{1}{3}.\dfrac{1}{5}=\dfrac{1}{10}+\dfrac{1}{15}=\dfrac{1}{6}\)
Cách 1:
(23×45)×56=815×56=8×515×6=2×2×2×53×5×2×3=49(23×45)×56=815×56=8×515×6=2×2×2×53×5×2×3=49
Cách 2:
(23×45)×56=23×(45×56)=23×46=2×43×6=2×43×2×3=49(23×45)×56=23×(45×56)=23×46=2×43×6=2×43×2×3=49
Cách 1:
(12+13)×15=(3+26)×15=56×15=16(12+13)×15=(3+26)×15=56×15=16
Cách 2:
(12+13)×15=12×15+13×15=110+115=330+230=530=16

a: =8/15x1/4=2/15
b: \(=\dfrac{5}{3}\cdot\dfrac{4}{5}\cdot\dfrac{6}{7}=\dfrac{24}{21}=\dfrac{8}{7}\)
c: \(=\dfrac{2}{5}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{2}{5}\)


giúp mình, mình sắp thi
7/12
11/6