Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
24 x 235 x 2 - 4 x 226 x 12 + 48
= 48 x 235 - 48 x 226 + 48
= 48 x (235 - 226 + 1)
= 48 x 10
= 480
24 x 235 x 2 - 4 x 226 x 12 + 48
= 48 x 235 - 48 x 226 + 48
= 48 x (235 - 226 + 1)
= 48 x 10 = 480
a x 12 - a = 55
a x (12 - 1) = 55
a x 11 = 55
=> a = 4
Vậy a = 4
Chúc em học tốt!!!
\(\dfrac{2}{13}\times12=\dfrac{2}{13}\times\dfrac{12}{1}=\dfrac{24}{13}\)
\(1-\dfrac{5}{6}=\dfrac{1}{1}-\dfrac{5}{6}=\dfrac{6}{6}-\dfrac{5}{6}=\dfrac{1}{6}\)
\(\dfrac{5}{7}+\dfrac{1}{3}=\dfrac{15}{21}+\dfrac{7}{21}=\dfrac{22}{21}\)
a) 142 x 12 + 142 x 18
= 142 x ( 18 + 12 )
= 142 x 30
= 4260
b) 49 . 365 - 39 . 365
= 365 . ( 49 - 39)
= 365 . 10
= 3650
c) 4 . 18 . 25
= 18 . 4 . 25
= 18 . 100
= 1800
` 3/7 + 3/4 - 1/2 = 12/28 + 21/28 - 14/28 = 33/28 - 14/28 = 19/28`
` 6/11 + 2/9 xx 12 = 6/11 + 8/3 = 18/33 + 88/33 = 106/33`
` 5/7 - 8/5 : 4 = 5/7 - 8/5 xx 1/4 = 5/7 - 2/5 = 25/35- 14/35 = 11/35`
\(\dfrac{3}{7}+\dfrac{3}{4}-\dfrac{1}{2}=\dfrac{12}{28}+\dfrac{21}{28}=\dfrac{33}{28}-\dfrac{1}{2}=\dfrac{33}{28}-\dfrac{14}{28}=\dfrac{19}{28}\)
\(\dfrac{6}{11}+\dfrac{2}{9}\times12=\dfrac{54}{99}+\dfrac{22}{99}=\dfrac{76}{99}\times12=\dfrac{76\times12}{99}=\dfrac{912}{99}\)
\(\dfrac{5}{7}-\dfrac{8}{5}:4=\dfrac{5}{7}-\dfrac{8}{4}\times\dfrac{1}{4}=\dfrac{5}{7}-\dfrac{1}{2}=\dfrac{10}{14}-\dfrac{7}{14}=\dfrac{3}{14}\)
Cách 1:
A. \(\dfrac{17}{19}\) x \(\dfrac{12}{15}\) x \(\dfrac{19}{17}\)
= (\(\dfrac{17}{19}\) x \(\dfrac{19}{17}\)) x \(\dfrac{12}{15}\)
= \(1\) x \(\dfrac{12}{15}\)
= \(\dfrac{4}{5}\)
Cách hai:
A; \(\dfrac{17}{19}\) x \(\dfrac{12}{15}\) x \(\dfrac{19}{17}\)
= \(\dfrac{68}{95}\) x \(\dfrac{19}{17}\)
= \(\dfrac{4}{5}\)
câu A cách 1
\(\dfrac{17}{19}\times\dfrac{12}{15}\times\dfrac{19}{17}\)
=\(\dfrac{17\times12\times19}{19\times15\times17}\)
=\(\dfrac{12}{15}\)
câu A cách 2
\(\dfrac{17}{19}\times\dfrac{12}{15}\times\dfrac{19}{17}\)
=\(\dfrac{17}{19}\times\dfrac{19}{17}\times\dfrac{12}{15}\)
=1 x \(\dfrac{12}{15}\)
=\(\dfrac{12}{15}\)
4869 x 12 = 58428
12 x 25 = 300
98 x 10 = 980