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\(A=\dfrac{7}{19}\cdot\dfrac{8}{11}+\dfrac{7}{19}\cdot\dfrac{3}{11}+\dfrac{12}{19}\\ A=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)+\dfrac{12}{19}\\ A=\dfrac{7}{19}\cdot1+\dfrac{12}{19}\\ A=\dfrac{19}{19}=1\)
A = 7/19.8/11+7/19.3/11+12/19
A = 7/19. . (8/11 + 3/11) + 12/19
A = 7/19 . 1 + 12/19
A = 7/19 + 12/19
A = 1
A=7/19.8/11+7/19.3/11+12/19
A=7/19.(8/11+3/11)+12/19
A=7/19.1+12/19
A=7/19+12/19
A=1
Ai có lòng tốt
cho mình một
tích đúng nhé.
Bài làm
\(A=\frac{7}{19}.\frac{8}{11}+\frac{7}{19}.\frac{3}{11}+\frac{12}{19}\)
\(A=\frac{7}{19}.\left(\frac{8}{11}+\frac{3}{11}\right)+\frac{12}{19}\)
\(A=\frac{7}{19}.1+\frac{12}{19}\)
\(A=\frac{7}{19}+\frac{12}{19}\)
\(A=1\)
a) (- 25) x 125,4 x (-8) x (-17)
= (- 25 x 4) x (- 8 x 125) x (-17)
= (-100) x (-1000) x (-17)
= - 1 700 000
b) \(\frac{-3}{4}+\frac{2}{7}+\frac{-1}{4}+\frac{3}{5}+\frac{5}{7}\)
\(=\left(\frac{-3}{4}+\frac{-1}{4}\right)+\left(\frac{2}{7}+\frac{5}{7}\right)+\frac{3}{5}\)
\(=-1+1+\frac{3}{5}\)
\(=0+\frac{3}{5}=\frac{3}{5}\)
c) \(\frac{7}{19}.\frac{8}{11}+\frac{7}{19}.\frac{3}{11}-\frac{12}{19}\)
\(=\frac{7}{19}.\left(\frac{8}{11}+\frac{3}{11}\right)-\frac{12}{19}\)
\(=\frac{7}{19}.1-\frac{12}{19}\)
\(=\frac{7}{19}-\frac{12}{19}=\frac{-5}{19}\)
d) \(19\frac{5}{8}:\frac{7}{2013}-26\frac{5}{8}:\frac{7}{2013}\)
\(=\left(19\frac{5}{8}-26\frac{5}{8}\right):\frac{7}{2013}\)
\(=-7:\frac{7}{2013}\)
\(=-2013\)
e) \(\frac{-5}{12}.\frac{2}{11}+\frac{-5}{12}.\frac{9}{11}+\frac{5}{12}\)
\(=\frac{-5}{12}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{5}{12}\)
\(=\frac{-5}{12}.1+\frac{5}{12}\)
\(=\frac{-5}{12}+\frac{5}{12}=0\)
~Học tốt~
\(\frac{7}{19}.\frac{8}{11}+\frac{7}{19}\)
\(=\frac{7}{19}.\frac{8}{11}+\frac{7}{19}.1\)
\(=\frac{7}{19}.\left(\frac{8}{11}+1\right)\)
\(=\frac{7}{19}.\frac{19}{11}\)
\(=\frac{7}{11}\)
7/19 . 8/11 + 7/19 . 3/11 + 12/19
= 7/19 . ( 8/11 + 3/11 ) + 12/19
= 7/19 . 1 + 12/19
=7/19 + 12/19
= 1
Hi vọng các bạn nha
Bài 6:
a: \(x=-\dfrac{2}{3}-\dfrac{1}{7}=\dfrac{-14-3}{21}=\dfrac{-17}{21}\)
d: \(x=\dfrac{9}{10}\cdot\dfrac{-5}{9}=\dfrac{-1}{2}\)
e: \(\Leftrightarrow x\cdot\dfrac{1}{3}=\dfrac{14}{21}-\dfrac{3}{21}=\dfrac{11}{21}\)
=>x=11/7
=7/19.(8/11+3/11)
=7/19.1
=7/19
=7/19.(8/11+3/11)
=7/19.1
=7/19