b) 2x + 15 = -27

2x = -27 - 15

2x = -42

x = -42 : 2

x = -21

c) -765 - (305 + x) = 100

305 + x = -765 - 100

305 + x = -865

x = -865 - 305

x = -1170

d) 2^x : 4 = 16

2^x = 16 x 4

2^x = 64

2^x = 2⁶

⇒ x = 6

e) 128 - 3.(x + 4) = 23

3.(x + 4) = 128 - 23

3.(x + 4) = 105

x + 4 = 105 : 3

x + 4 = 35

x = 35 - 4

x = 31

76500

=765x(45+50+5)

=765x100

=76500

あ りがと う ござ いま した

 \(\left(x-10\right)\cdot11=22\\ x-10=\dfrac{22}{11}\\ x-10=2\\ x=2+10=12\)

--------------------------------------

\(2x+15=-27\\ 2x=-27-15\\ 2x=-42\\ x=-\dfrac{42}{2}=-21\)

---------------------------------------

\(-765-\left(305+x\right)=100\\ -305-x=100+765\\ -305-x=865\\ -x=865+305=1170\\ x=-1170\)

---------------------------------------

\(2^x\div4=16\\ 2^x=16\cdot4\\ 2^x=64\\ 2^x=2^6\\ x=6\)

tương đương hay suy ra ?

a) ( x -10 ) . 11 = 22

     ( x - 10 ) = 22 : 11

       x - 10 = 2

       x        = 10 + 2

       x        = 12

b) 2x + 15 = - 27

    2x = - 27 - 15

    2x = - 42

      x = - 42 : 2

      x = -21

c ) - 765 - ( 305 + x ) = 100

                 ( 305 + x ) = ( - 765 ) - 100

                   305 + x = - 865

                             x = ( - 865 ) - 305

                             x = - 1170

d ) 2^x : 4 = 16

     2^x = 16 : 4

     2^x = 4

     2^x = 4² 

=> x = 2

a, (x – 10).11 = 22

=>x-10=22:11

=>x-10=1

=>x=1+10

=>x=11

d)2^x:4=16

=>2^x=64

=>2⁶=64

=>x=6

2. a, \(\dfrac{x}{9}=\dfrac{2}{3}\Leftrightarrow3x=2.9\)
<=> 3x = 18
<=> x = 6
@Hà Thái

2b) \(\left(2+3+4+...+2004\right).x=2016.2013\)

Ta có : Từ 2 đến 2004 có : 2004-2+1=2003 (số hạng)

\(\Rightarrow2+3+4+...+2004=\dfrac{\left(2+2004\right).2003}{2}=2009009\)

\(\Rightarrow2009009x=2016.2013\)

\(\Rightarrow x=\dfrac{2016.2013}{2009009}\approx2\)

1. a, \(\dfrac{6}{7}:\left(\dfrac{1}{2}.\dfrac{3}{4}\right)-\dfrac{5}{8}\)

= \(\dfrac{6}{7}:\dfrac{3}{8}-\dfrac{5}{8}\)

= \(\dfrac{16}{7}-\dfrac{5}{8}\)

= \(\dfrac{93}{56}\)
@Hà Thái

765-678=87

mk chưa có

cn bn?

*girl2k6*

mk có rùi

kb nhé

=40

=87

học tốt 

ko có cr cx ko có ny

#Somebody addfriend with me#

1 + 2 + 6 + 4 + 87 + 32 + 543 + 654 + 765 

= ( 6 + 654 ) + ( 1 + 2 + 87 ) + ( 765 + 32 + 4 ) + 543

= 660 + 90 + 801 + 543

= 2094 

= 2094

1+2+6+4+87+32+543+654+765

=(765+1+2+4)+(654+6)+(543+87)

=772+660+630

=772+1290

=2062

giúp mik nhé cám ơn

16

=28