6: \(\Leftrightarrow x-8=20\)

hay x=28

a)  =49x(77+23) -30^2

     = 49 x100 -900

     = 4900-900 = 4000

b) =44x( 77+23) -20^2

    = 44x100 -400

    = 4400-400 = 4000

Hok hành chăm chỉ nha

a) 49. 77- 30²+ 23. 49

= 49 . 77 + 23 . 49 - 30²

= 49 . ( 77 + 23 ) - 900

= 49 . 100 - 900

= 4900 - 900

= 4000

b) 44. 77- 20²+ 23. 44

= 44 . 77 + 23 . 44 - 20²

= 44 . ( 77 + 23 ) - 400

= 44 . 100 - 400

= 4400 - 400

= 4000

~ HOK TỐT ~

a: \(\left(-2\right)^5+\left\lbrack\left(-7\right)^3:49+23\right\rbrack:\left(-2\right)\)

\(=-32+\left(-343:49+23\right):\left(-2\right)\)

\(=-32+\left(-7+23\right):\left(-2\right)=-32+16:\left(-2\right)\)

=-32-8

=-40

b: \(128\left(278-302\right)+278\left(302-128\right)\)

\(=128\cdot278-128\cdot302+278\cdot302-278\cdot128\)

\(=278\cdot302-128\cdot302=302\cdot150=45300\)

23.49+77.177+23.61-77.67

=23.(49+61)+77.(177-67)

=23.110+77.110

=110.(23+77)

=110.100=11000

k nha

23 * 49 + 77*177 + 23*61 - 77* 67 = 23(49+ 61) + 77 (177 - 67) = 23* 110 + 77* 110 = (23+ 77) * 110 = 100 * 110 = 11 000

kết quả là 16 nha bạn

49. (-23 + 2.x) = (-49).(-23 + 14)

49. (-23 + 2.x) = (-49). (-9)

49. (-23 + 2.x) = 441

     -23 + 2.x = 441 : 49

     -23 + 2.x = 9

             2.x = 9 - (-23)

            2.x = 32

              x = 32 : 2

              x = 16

   \(\dfrac{11}{4}\) \(\times\) 49 : \(\dfrac{77}{2}\) 

= \(\dfrac{11}{4}\) x 49 x \(\dfrac{2}{77}\) 

=  \(\dfrac{11\times7\times7\times2}{4\times11\times7}\)

= \(\dfrac{7}{2}\)

\(\dfrac{11}{4}.9:\dfrac{77}{2}\)

\(=\dfrac{11}{4}.9.\dfrac{22}{7}\)

\(=\dfrac{11.7.7.2}{4.11.7}\)

\(=\dfrac{7}{2}\)

ngu như con lợn lò

5x7x77-7x60+49x25-15x42=2870

   23 x 50 + 49 x 23 + 23

= 23 x 50 + 49 x 23 + 23 x 1 

= 23 x ( 50 + 49 + 1 )

= 23 x 100

= 2300

23 x 50 + 49 x 23 + 23

= 1150 + 1129 + 23

= 2302