ai biết ko ?

a=25x(725+250+25)

  =25x1000

  =25000

cái b tôi ko biết'

\(\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\left(\dfrac{1}{12}+\dfrac{2}{4}\right)\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\left(\dfrac{1}{12}+\dfrac{6}{12}\right)\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\dfrac{7}{12}\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{36}{60}\right)-\dfrac{35}{60}\right]\\ =\dfrac{3}{4}-\left(-\dfrac{71}{60}\right)\\ =\dfrac{3}{4}+\dfrac{71}{60}\\ =\dfrac{35}{60}+\dfrac{71}{60}\\ =\dfrac{106}{60}\\ =\dfrac{53}{30}\)

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\(-\dfrac{6}{7}.\dfrac{21}{12}\\ =-\dfrac{126}{84}\\ =-\dfrac{63}{42}\\ =-\dfrac{31}{14}\)

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\(\left(-5\right).\left(-\dfrac{6}{20}\right)\\ =\dfrac{\left(-5\right).\left(-6\right)}{20}\\ =\dfrac{30}{20}\\ =\dfrac{3}{2}\)

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\(-\dfrac{31}{36}:\left(-\dfrac{37}{72}\right)\\ =-\dfrac{31}{36}.\left(-\dfrac{72}{37}\right)\\ =\dfrac{2322}{1332}\)

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\(\left(-\dfrac{5}{17}\right):\left(-15\right)\\ =\left(-\dfrac{5}{17}\right).\left(-\dfrac{1}{15}\right)\\ =\dfrac{5}{255}\\ =\dfrac{1}{51}\)

\(\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\left(\dfrac{1}{12}+\dfrac{2}{4}\right)\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\left(\dfrac{1}{12}+\dfrac{6}{12}\right)\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\dfrac{7}{12}\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{36}{60}\right)-\dfrac{35}{60}\right]\\ =\dfrac{3}{4}-\left(-\dfrac{71}{60}\right)\\ =\dfrac{3}{4}+\dfrac{71}{60}\\ =\dfrac{35}{60}+\dfrac{71}{60}\\ =\dfrac{106}{60}\\ =\dfrac{53}{30}\)

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\(-\dfrac{6}{7}.\dfrac{21}{12}\\ =-\dfrac{126}{84}\\ =-\dfrac{63}{42}\\ =-\dfrac{31}{14}\)

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\(\left(-5\right).\left(-\dfrac{6}{20}\right)\\ =\dfrac{\left(-5\right).\left(-6\right)}{20}\\ =\dfrac{30}{20}\\ =\dfrac{3}{2}\)

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Bài 1:

1: =15+37+52-37-17=52-2=50

2: =38-42+14-25+27+15=62-42+29=20+29=49

Bài 1: Bỏ ngoặc rồi tính

3) (21-32) - (-12+32)=21-32-(-12)-32=21-32+12-32=-31

4) (12+21) - (23-21+10)=12+21-23+21-10=21

5) (57-725) - (605-53)=57-725-605+53=-1220

6) (55+45+15) - (15-55+45)=55+45+15-15+55-45=55+55=110

Bài 2: Tính các tổng sau một cách hợp lí

1) (-37) + 14 + 26 + 37=(-37+37)+(14+26)=0+40=40

2) (-24) +6 + 10 + 24=(-24+24)+(6+10)=0+16=16

3) 15 + 23 + (-25) + (-23)=(15-25)+(23-23)=-10+0=-10

4) 60 + 33 + (-50) + (-33)=(60-50)+(33-33)=10+0=10

5) (-16) + (-209) + (-14) + 209=(-16-14)+(-209+209)=-30+0=-30

6) (-12) + (-13) + 36 + (-11)=(-11-12-13)+36=-36+36=0

=15+37+52-37-17 =(37-37)+52+15-17 =0+52+15-17 =67-17 =50

(38 – 42 + 14) – (25 – 27 – 15) =38-42+14-25+27+15 =27 c. -(21 – 32) – (-12 + 32) =-21+32+12-32 =-9 d. -(12 + 21 – 23) - (23 – 21 + 10) =-12-21+23-23+21-10 =-22 e. (57 – 725) – (605 – 53) =57-725-605+53 =-1220 f. (55 + 45 + 15) – (15 – 55 + 45) =55+45+15-15+55-45 =110

a) x+l- 5l = l-37l

x=37-5

x=32

b)lxl= 54 : 6

   lxl=9

Bạn chỉ  mình viết cái dấu giá trị tuyệt đối mình giải cho

( x + 2 ) + ( x + 4 ) + ( x + 6 ) + ... + ( x + 50 ) = 725

<=> 25x + (2 + 4 + 6 + ..... + 50) = 725

<=> 25x + 650 = 725

=> 25x = 725 - 650

=> 25x = 75

=> x = 75 : 25

=> x = 3

25x+650=725

=>25x=725-650=75

=>x=75/25=3

t i c k cho mình nha

So sánh các số ta có:

19 624 < 20 001 < 29 815 < 37 109 < 48 725

Vậy các số đã cho được sắp xếp theo thứ tự từ bé đến lớn là:

19 624 ; 20 001 ; 29 815 ; 37 109 ; 48 725.

\(\left[0,\left(37\right)+0,\left(7\right)\right]x=0,1\left(6\right)\)

\(\Rightarrow\left[\frac{37}{99}+\frac{7}{9}\right]x=0,1+0,0\left(6\right)\)

\(\Rightarrow\frac{38}{33}.x=\frac{1}{10}+\frac{6}{90}\)

\(\Rightarrow\frac{38}{33}.x=\frac{1}{6}\)

\(\Rightarrow x=\frac{1}{6}:\frac{38}{33}=\frac{1}{6}.\frac{33}{38}\)

\(\Rightarrow x=\frac{11}{76}\)

Vậy \(x=\frac{11}{76}\)

b, xy-x+2y=3

<=> xy-x+2y-3=0

<=>x(y-1)+2(y-1)-1=0

<=> (y-1)(x+2) =1

Ta có bảng sau

Vậy...