( 2015 - x ) : 29 + 32 = 100

( 2015 - x ) : 29 = 100 - 32

( 2015 - x ) : 29 = 68

2015 - x = 68 x 29

2015 - x = 1972

x = 2015 - 1972

x = 43

L i k e nha các bạn !!!

(2015-x):26=100-32

(2015-x):26=68

2015-x=68x26

2015-x=1768

x=2015-1768

x=247
 

Ta co : 

(2015 - x):29+32=100

(2015-x):29       = 100 - 32

(2015-x):29       = 68

2015-x             = 68 . 29

2015-x             = 1972

x                      = 2015 - 1972

x                      =43

\(\left(2009-x\right):29+32=100\\ =>\left(2009-x\right):29=100-32=68\\ =>2009-x=68.29=1972\\ =>x=2009-1972=37\)

-

\(\left(x-2\right).3-270:45=120\\ =>3\left(x-2\right)-6=120\\ =>3\left(x-2\right)=120+6=126\\ =>x-2=126:3=42\\ =>x=42+2=44\)

#)Giải :

a)\(\left(x-149\right)\div35=270\)

\(\Leftrightarrow x-149=9450\)

\(\Leftrightarrow x=9599\)

\(a,(x-149):35=270\)

\(\Leftrightarrow x-149=9450\)

\(\Leftrightarrow x=9450+149=9599\)

Vậy x = 9599

\(b,(2009-x):29+32=100\)

\(\Leftrightarrow(2009-x):29=68\)

\(\Leftrightarrow2009-x=1972\)

\(\Leftrightarrow x=2009-1972=37\)

Vậy x = 37

\(c,x+472=918\)

\(\Leftrightarrow x=918-472=446\)

Vậy x = 446

a) (x - 149) : 35 = 270

              x - 149 = 270 . 35

               x - 149 = 9450

                        x = 9450 + 149

                        x = 9599

b) (2009 - x) : 29 + 32 = 100

            (2009 - x) : 29 = 100 - 32

            (2009 - x) : 29 = 68

                     2009 - x = 68 x 29

                    2009 - x = 1972

                               x = 2009 - 1972

                               x = 37

c) x + 172 = 918

              x = 918 - 472

              x = 446

6666 +8888=

6666 + 8888 = 15554

Chúc các bạn học tốt

a) \(\frac{7}{x}+\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}=\frac{29}{45}\)

\(\Rightarrow\frac{7}{x}+\left(\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}\right)=\frac{29}{45}\)

\(\Rightarrow\frac{7}{x}+\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{41}-\frac{1}{45}\right)=\frac{29}{45}\)

\(\Rightarrow\frac{7}{x}+\left(\frac{1}{5}-\frac{1}{45}\right)=\frac{29}{45}\)

\(\Rightarrow\frac{7}{x}+\frac{8}{45}=\frac{29}{45}\)

\(\Rightarrow\frac{7}{x}=\frac{29}{45}-\frac{8}{45}\)

\(\Rightarrow\frac{7}{x}=\frac{7}{15}\)

\(\Rightarrow x=15\)

Vậy x = 15

b) \(\frac{x}{2008}-\left(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\right)=\frac{5}{8}\)

\(\Rightarrow\frac{x}{2008}-\left(\frac{2}{20}+\frac{2}{30}+\frac{2}{42}+...+\frac{2}{240}\right)=\frac{5}{8}\)

\(\Rightarrow\frac{x}{2008}-\left(\frac{2}{4.5}+\frac{2}{5.6}+\frac{2}{6.7}+...+\frac{2}{15.16}\right)=\frac{5}{8}\)

\(\Rightarrow\frac{x}{2008}-2\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+...+\frac{1}{15}-\frac{1}{16}\right)=\frac{5}{8}\)

\(\Rightarrow\frac{x}{2008}-2\left(\frac{1}{4}-\frac{1}{16}\right)=\frac{5}{8}\)

\(\Rightarrow\frac{x}{2008}-2.\frac{3}{16}=\frac{5}{8}\)

\(\Rightarrow\frac{x}{2008}-\frac{3}{8}=\frac{5}{8}\)

\(\Rightarrow\frac{x}{2008}=\frac{5}{8}+\frac{3}{8}\)

\(\Rightarrow\frac{x}{2008}=1\)

\(\Rightarrow x=2008\)

Vậy x = 2008

_Chúc bạn học tốt_

bài 2 tìm x

a,106- ( x+ 7) =9

x+7 = 106 - 9

x+7 = 107

x= 107 - 7

x=100

b, 2 x ( x+ 4) + 5 =65

2 x (x+4) = 65 - 5

2 x (x+4) = 60

x+4 = 60:2

x+4= 30

x= 30 - 4

x=26

c, (16x x -32) x 45=0

16 x X - 32 = 0: 45

16 x X - 32 =0

16 x X = 0 + 32

16 x X = 32

X= 32:16

X=2

d, x+4 x x = 100 : 5

X + 4 x X = 20

(1+4) x X = 20

5 x X  = 20

X= 20:5

X=4

Bài 1:

a, 24 x 66 - 24 + 36 x 24

= 24 x (66-1+36)

= 24 x 101

= 24 x 100 + 24

= 2400+24

=2424

b, 29 x 173 - 29 x 72 - 29

= 29 x (173 - 72 -1)

= 29 x 100

= 2900

c, 1+5+10+15+...+55+60

= (5+60) x 6 + 1 (có 6 cặp)

= 65 x 6 + 1

= 390 +1 =391

d, D= 1 x 2 + 2 x 3 + 3 x 4 +...+18 x 19 + 19 x 20

3D= 1 x 2 x 3+ 2 x 3 x (4-1) + 3 x 4 x (5-2) +...+ 18 x 19 x (20 - 17) + 19 x 20 x (21-18)

3D= 1 x 2 x 3 - 1 x 2 x 3 + 2 x 3 x 4 - 2 x 3 x 4 +.... + 19 x 20 x 21 - 18 x 19 x 20

3D= 19 x 20 x 21 =7980

=> D= 7980:3=2660

  x = 5    y = 36

  ( 18 / 21 + 3 / 21 ) + ( 19 / 32 + 13 / 32 ) + ( 75 / 100 + 1 / 4 )

= 1 + 1 + 1 = 3

2008/2009 >  2010/2011 ; 1999/2001 < 12/11 ;2007/2006>  2006/2007 ; 101/100 >100/101

1. 

    x = 5

    y = 36

2.

  ( 18 / 21 + 3 / 21 ) + ( 19 / 32 + 13 / 32 ) + ( 75 / 100 + 1 / 4 ) = 1 + 1 + 1 = 3

3.

   >     ;    <       ;    >        ;        >

  x = 5    y = 36

  ( 18 / 21 + 3 / 21 ) + ( 19 / 32 + 13 / 32 ) + ( 75 / 100 + 1 / 4 )

= 1 + 1 + 1 = 3

2008/2009 >  2010/2011 ; 1999/2001 < 12/11 ;2007/2006>  2006/2007 ; 101/100 >100/101

( 2009 - x ) : 29 + 32 = 100

( 2009 - x ) : 29        = 100 - 32 

( 2009 - x ) : 29        = 68 

( 2009 - x )              = 68 . 29  

  2009 - x                = 1972

            x                = 2009 - 1972

            x                = 37

[2009 - x] : 29 =100-32

[2009-x] : 29 =68

2009-x =68x29

2009-x=1972

x=2009-1972

x=37

(2009-x):29+32=100

=>(2009-x):29=100-32

=>(2009-x):29=68

=>2009-x=68x29

=>2009-x=1972

=>x=2009-1972

=>x=37

(2009-x) : 29 + 32 = 100

(2009-x): 29 = 68

2009-x = 68 x 29

2009 - x = 2001

x= 2009 - 2001

x=8

( 2009 - x ) : 29 + 32 = 100

( 2009 - x ) : 29 = 100 - 32

( 2009 - x ) : 29 = 68

  2009 - x = 68 x 29

  2009 - x = 1972

            x = 2009 - 1972

            x = 37