1) 3/9 + 5/9 = 8/9

2) 1/2 x 2/3 x 3/4 x 4/5

= 1/5

(1-1/2)×(1-1/3)×(1-1/4)×(1-1/5)×1-1/6=1/2×2/3×3/4×4/5×5/6=1/6

\(\frac{x+5}{2005}+\frac{x+6}{2004}+\frac{x+7}{2003}=-3\)

\(\Leftrightarrow\frac{x+5}{2005}+1+\frac{x+6}{2004}+1+\frac{x+7}{2003}+1=0\)

\(\Leftrightarrow\frac{x+2010}{2005}+\frac{x+2010}{2004}+\frac{x+2010}{2003}=0\)

\(\Leftrightarrow x+2010=0\)

\(\Leftrightarrow x=-2010\).

a: \(=167\cdot\dfrac{67}{1000}+167\cdot\dfrac{33}{1000}=167\cdot\dfrac{1}{10}=\dfrac{167}{10}\)

giúp mình với

= 54 x 48 : 24

= 54 x (48 : 24)

= 54 x 2

= 108 

54 x ( 48 : 24 )

= 54 x 2

= 108 .

:33

1200-31/40=47969/40

câu 2 =45/56+25/56=(45+25)/56=70/56=5/4

`2022 \times 123 \times 12 - 2022 \times 11`

`= 2022 \times (123 \times 12 - 11)`

`= 2022 \times (1476 - 11)`

`= 2022 \times 1465`

`= 2962230`

TL:

=2,8×1,25+1,25×7,2=1,25×(2,8+7,2)=1,25×10=12,5

_HT_

1) \(=\left(\frac{3}{5}+\frac{2}{5}\right).\frac{6}{11}\)

\(=1.\frac{6}{11}\)

\(=\frac{6}{11}\)

2)\(\frac{17}{25}.\left(\frac{11}{19}+\frac{6}{19}+\frac{2}{19}\right)\)

\(=\frac{17}{25}.1\)

\(=\frac{17}{25}\)

2.\(\frac{17}{25}.\frac{11}{19}+\frac{17}{25}.\frac{6}{19}+\frac{17}{25}.\frac{2}{19}=\frac{17}{25}\left(\frac{11}{19}+\frac{6}{19}+\frac{2}{19}\right)\\ =\frac{17}{25}.1\\ =\frac{17}{25}\)

\(=82\times\left(10,5+3,2\right)+13,7\times18\)

\(=13,7\times82+18\times13,7\)

\(=13,7\times\left(18+82\right)\)

\(=13,7\times100=1370\)

=

= 82 x (10,5 + 3,2) + 13,7 x 18
= 82 x 13,7 + 13,7 x 18
= 13,7 x (82 + 18)
= 13,7 x 100
=1370