Bài 1: 

\(101\cdot125+101\cdot25-101\cdot50\)

\(=101\cdot\left(125+25-50\right)\)

\(=101\cdot100\)

\(=10100\)

Bài 2: 

\(76\cdot115+56\cdot24+59\cdot24\)
\(=76\cdot115+24\cdot\left(56+59\right)\)

\(=76\cdot115+24\cdot115\)

\(=115\cdot\left(76+24\right)\)

\(=115\cdot100\)

\(=11500\)

còn bài 3,4,5 thì sao ak 

b) 1449 - {[(216 + 184) : 8] . 9}

=  1449 - {[400 : 8] : 9}

=  1449 - {50 : 9}

=  1449 - \(\frac{50}{9}\)

=  \(\frac{12991}{9}\)

c) 342 . 163 + 337 . 342 - 10³ . 171

=  342 . (163 + 337) - 1000 . 171

=  342 . 500 - 500 . 2 . 171

=  500 . (342 - 2 - 171)

=  500 . 169

=  84500

3: 

\(=\dfrac{1}{7}\cdot\dfrac{3}{5}\cdot\dfrac{5}{6}\cdot\dfrac{5}{8}=\dfrac{1}{7}\cdot\dfrac{1}{2}\cdot\dfrac{5}{8}=\dfrac{5}{112}\)

4:

=>2/3:x=-2-1/3=-7/3

=>x=-2/3:7/3=-2/7

5:

AC=CB=12/2=6cm

IB=6/2=3cm

C

Bài 1:

a) \(\dfrac{19}{12}+\left|\dfrac{-5}{2}\right|+\left(\dfrac{3}{2}\right)^2=\dfrac{19}{12}+\dfrac{5}{2}+\dfrac{9}{4}\)

\(=\dfrac{19+5.6+9.3}{12}=\dfrac{76}{12}=\dfrac{19}{3}\)

b) \(\dfrac{2}{11}.\dfrac{16}{9}-\dfrac{2}{11}.\dfrac{7}{9}=\dfrac{2}{11}\left(\dfrac{16}{9}-\dfrac{7}{9}\right)=\dfrac{2}{11}.1=\dfrac{2}{11}\)

Bài 2:

Áp dụng t/c dtsbn:

\(\dfrac{a}{8}=\dfrac{b}{3}=\dfrac{a-b}{8-3}=\dfrac{55}{5}=11\)

\(\Rightarrow\left\{{}\begin{matrix}x=11.8=88\\b=11.3=33\end{matrix}\right.\)

Bài 4 là:

\(\dfrac{1}{2.5}\) + \(\dfrac{1}{5.8}\) +....+\(\dfrac{1}{92.95}\) + \(\dfrac{1}{95.98}\)

                  Đúng không bạn

đúng rồi

Bài 1:

\(-1000\rightarrow-100\rightarrow-43\rightarrow-15\rightarrow0\rightarrow105\rightarrow1000\)

Bài 1:

a) 210 + [46 + (-210)+(-26)]

= 210 + 46 - 210 - 26

= (210 - 210) + (46 - 26)

= 0 + 20

= 20

b) (-8) - [ (-5) + 8]

= (-8) + 5 - 8

= -3 - 8

= -11

c) 25. 134 + 25. (-34)

= 25. (-34 + 134)

= 25. 100

= 2500

Bài 2:

a) x + (-35) = 18

x = 18 + 35

x = 53

Vậy x = 53

b) -2x - (-17) = 15

17 - 15 = 2x

2 = 2x

x = 2 : 2

x = 1

Vậy x = 1

Bài 5:

a. (b - 2) = 3 = 1. 3 = (-1). (-3)

Vì \(a;b\inℤ\)nên ta có bảng sau:

Vậy \(\left(a;b\right)\in\left\{\left(1;5\right),\left\{3;3\right\},\left\{-1;-1\right\},\left\{-3;-1\right\}\right\}\)

Chúc bạn học tốt!!!

1449-[216-184:8).9]

=1449-[216-23).9]

=1449-(193.9)

=1449-1737

=-288

24 : { 300 : [ 375 ( 150 + 15 . 5 ) ] }

24 : { 300 : [ 375 ( 150 + 75 ) ] }

24 : [ 300 : ( 375 . 225 ) ]

24 : ( 300 : 84375 )

24 : 4/1125

= 6750

\(a,\left(\frac{3}{8}+-\frac{3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)

   =  \(\left(-\frac{3}{8}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)

    = \(\frac{5}{24}:\frac{5}{6}+\frac{1}{2}\)

     = \(\frac{1}{4}+\frac{1}{2}\)

      =  \(\frac{3}{4}\)

b)\(-\frac{7}{3}.\frac{5}{9}+\frac{4}{9}.\left(-\frac{3}{7}\right)+\frac{17}{7}\)

    =\(-\frac{35}{27}+\left(-\frac{4}{21}\right)+\frac{17}{7}\)

   = \(-\frac{35}{27}+\frac{47}{21}\)

   =        \(\frac{178}{189}\)

c) \(\frac{117}{13}-\left(\frac{2}{5}+\frac{57}{13}\right)\)

  = \(\frac{117}{13}-\frac{311}{65}\)

 =       \(\frac{274}{65}\)

d) \(\frac{2}{3}-0,25:\frac{3}{4}+\frac{5}{8}.4\)

= \(\frac{2}{3}-\frac{1}{4}:\frac{3}{4}+\frac{5}{8}.4\)

= \(\frac{2}{3}-\frac{1}{3}+\frac{5}{2}\)

=     \(\frac{1}{3}+\frac{5}{2}\)

=         \(\frac{17}{6}\)