785-954 = ... cảm ơn

e , 12 x 35 + 35 x 182 - 35 x 94 
=    35 x ( 12 + 182 - 94 )
=    35 x       100
=         3500.

n , 19 x 27 + 47 x 81 + 19 x 20
=   19 x 27 + 19 x 20 + 47 x 81 
=   19 x ( 27 + 20 ) + 47 x 81
=   19 x        47      + 47 x 81
=    47 x ( 19 + 81 )
=    47 x     100
=       4700. 
T I C K cho mik nha !
~ HT ~      

\(83\times14+27\times17+83\times13\)

\(=83\times\left(14+13\right)+27\times17\)

\(=83\times27+27\times17\)

\(=\left(83+17\right)\times27\)

\(=100\times27\)

\(=2700\)

Chúc bạn học tốt

$83\times 14+27\times 17+83\times 13$

$=83\times \left(14+13\right)+27\times 17$

$=83\times 27+27\times 17$

$=\left(83+17\right)\times 27$

$=100\times 27$

$=2700$

Chúc bạn học tốt

$83\times 14+27\times 17+83\times 13$

$=83\times \left(14+13\right)+27\times 17$

$=83\times 27+27\times 17$

$=\left(83+17\right)\times 27$

$=100\times 27$

$=2700$

Chúc bạn học tốt

Bài 6:

a)\(\left(-18\right)-\left(-3\right)-12\)

\(=\left(-18\right)+3-12\)

\(=-15-12\)

\(=-27\)

b)\(85.\left(35-27\right)-35.\left(85-27\right)\)

\(=85.35-85.27-35.85+35.27\)

\(=85.\left(35-27-35\right)+35.27\)

\(=85.\left(-27\right)+35.27\)

\(=27.\left(-85+35\right)\)

\(=27.\left(-50\right)\)

\(=-1350\)

c)\(\left(-45\right).69+31.\left(-45\right)\)

\(=\left(-45\right).\left(69+31\right)\)

\(=\left(-45\right).100\)

\(=-4500\)

Bài 7:

a)\(\left(2-x\right)+10=-14\)

\(\Rightarrow2-x=-24\)

\(\Rightarrow x=26\)

b)\(14.\left|x\right|=28\)

\(\Rightarrow\left|x\right|=2\)

\(\Rightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)

c)\(31-\left(17+x\right)=55\)

\(\Rightarrow17+x=-24\)

\(\Rightarrow x=-41\)

(-18)-(-3)-12=-27

85.(35-27)-35.(85-27)=-1350

(-45).69+31.(-45)=-4500

(2-x)+10=-14

\(\Leftrightarrow\)(2-x)=-14-10

\(\Leftrightarrow\)2-x=-24

\(\Rightarrow\)x=2-(-24)

\(\Rightarrow\)x=26

14.lxl=28

\(\Leftrightarrow\)lxl=28:14

\(\Leftrightarrow\)lxl=2

\(\Rightarrow\)x=-2

1)tính

a)\(-17+\left(-19\right)+25\)

\(=-17-19+25\)

\(=-\left(17+19\right)+25\)

\(=-36+25\)

\(=-\left(36-25\right)\)

\(=-11\)

b)\(-26+\left(-25\right)-18\)

\(=-26-25-18\)

\(=-\left(26+25\right)-18\)

\(=-51-18\)

​\(=-\left(51+18\right)\)​

\(=-69\)

c)\(35-\left(-19\right)-19-8\)

\(=35+19-19-8\)

\(=35+\left(19-19\right)-8\)

\(=35+0-8\)

\(=35-8\)

\(=27\)

d)\(1963-\left(-180\right)-1990\)

\(=1963+180-1990\)

\(=2143-1990\)

\(=153\)

2)Tìm x thuộc z biết

a)\(x-\left(-18\right)=25+\left(-17\right)\)

\(\Leftrightarrow x+18=25-17\)

\(\Leftrightarrow x+18=8\)

\(\Leftrightarrow x=8-18\)

\(\Leftrightarrow x=-10\)

Vậy x=-10

b)\(x-28=-27-30\)

\(\Leftrightarrow x-28=-\left(27+30\right)\)

\(\Leftrightarrow x-28=-57\)

\(\Leftrightarrow x=-57+28\)

\(\Leftrightarrow x=-\left(57-28\right)\)

\(\Leftrightarrow x=-29\)

Vậy x=-29

c)\(35-\left(-x\right)=27-18-\left(-8\right)\)

\(\Leftrightarrow35+x=27-18+8\)

\(\Leftrightarrow35+x=9+8\)

\(\Leftrightarrow35+x=17\)

\(\Leftrightarrow x=17-35\)

\(\Leftrightarrow x=-18\)

Vậy x=-18

d)\(40+\left(-x\right)=35-\left(-27\right)\)

\(\Leftrightarrow40-x=35+27\)

\(\Leftrightarrow40-x=62\)

\(\Leftrightarrow x=40-62\)

\(\Leftrightarrow x=-22\)

Vậy x=-22

\(a.=\dfrac{2019}{2020}\times\left(\dfrac{4}{11}+\dfrac{5}{11}+\dfrac{2}{11}\right)\\ =\dfrac{2019}{2020}\times1=\dfrac{2019}{2020}\\ b.=\dfrac{25}{27}\times\left(\dfrac{17}{14}-\dfrac{1}{14}-\dfrac{2}{14}\right)\\ =\dfrac{25}{27}\times1=\dfrac{25}{27}\)

Thanks mik chữ cũng hơi ẩu

a. => 225-x=135

=> x=225-135

Vậy x=90.

b. => 7.(x-14)+35=25+31

=> 7.(x-14)=25+31-35

=> 7.(x-14)=21

=> x-14=3

=> x=3+14

Vậy x=17

c. => 7^x:7²=7²⁷

=> 7^x-2=7²⁷

=> x-2=27

=> x=27+2

Vậy x=29.

     43 x 27 + 93 x 43 + 57 x 61 + 59 x 57 

  = 43 x ( 27 + 93 ) + 57 x ( 61 + 59 )

  =  43 x 120 +  57 x 120

  = 120 x ( 43 + 57 )

   = 120 x 100

  = 1200

b) 64 x 6 + 81 x 4 + 17 x 6 

 = 6 x ( 64 + 17 ) + 81 x 4 

 =  6 x 81 + 81 x 4 

 = 81 x ( 6 + 4 ) 

 = 81 x 10 

 = 810

A) =43 x (27+93)+57*(61+59)

=43*120+57*120

=120*(43+57)

=120*100

=12000

Bài 6: Thực hiện phép tính

a)(-18)-(-3)-12

= (-18) + 3 - 12

= (-15) - 12

= - 3

b)85.(35-27)-35.(85-27)

= 85. 8 - 35. 58

= 680. 2030

= 1380400

c)(-45).69+31.(-45)

= (-45) . (69 + 31)

= (-45) . 100

= - 4500

Bài 7:Tìm x thuộc Z, biết:

a)(2-x)+10=-14

2-x = 14 - 10

2-x = 4

x = 2 - 4

x = - 2

b)14.|x|=28

|x| = 28 : 14

|x| = 2

⇒ x ϵ {2;-2}

a) 27 x 35 + 73 x 6 - 27 x 29

= 27 x ( 35 - 29 ) + 73 x 6

= 27 x 6 + 73 x 6

= 6 x ( 27 + 73 )

= 6 x 100

= 600

b) 29 x ( 47 + 53 ) - 47 x ( 29 + 53 )

= 29 x 47 + 29 x 53 - 47 x 29 + 47 x 53

= 29 x ( 47 + 53 - 47 ) + 47 x 53

= 29 x 53 + 47 x 53

= 53 x ( 29 + 47 )

= 53 x 76

= 4028

c) 5 x 17 x 4 x 25 x 20

= ( 5 x 20 ) x ( 4 x 25 ) x 17

= 100 x 100 x 17

= 10000 x 17

= 170000

Mới lớp 3!

lớp 3 cút , ng ta nói hơn lớp 6 mak