a) |x + 4| = 17

=> \(\orbr{\begin{cases}x+4=17\\x+4=-17\end{cases}}\)

=> \(\orbr{\begin{cases}x=13\\x=-21\end{cases}}\)

b) (7 - x) - (25 + 7) = -25

=> (7 - x) - 32 = -25

=> 7 - x = -25 + 32

=> 7 - x = 7

=> x = 7 - 7

=> x = 0

c. |x + 5| = |-7|

=> |x + 5 | = 7

=> \(\orbr{\begin{cases}x+5=7\\x+5=-7\end{cases}}\)

=> \(\orbr{\begin{cases}x=2\\x=-12\end{cases}}\)

2) 4 . (-5)² + 2 . (-15)

= 2. 2 . 25 + 2 . (-15)

= 2.(2 . 25 - 15)

= 2 . 35

= 70

1/ 

a) | x+4 | = 17

\(\Rightarrow\)x+4 = 17 hoặc x+4 = -17

        x      = 13         x      = -21

b) ( 7 - x ) - ( 25 + 7 ) = -25

     7 - x                      = -25 + 25 + 7

     7 - x                      = 7

          x                      = 0

c) | x + 5 | = 7

\(\Rightarrow\)x + 5 = 7 hoặc x + 5 = -7

         x        = 2         x        = -12

2/

    4 . ( -5 )² + 2 . ( -15 )

= 4 . 25 + 2 . ( -15 )

= 100 + ( -30 )

= 70

Hk tốt

\(9\frac{7}{25}+\frac{3}{25}\cdot\frac{7}{11}-\frac{7}{25}\cdot\frac{14}{11}\)

\(=9\frac{7}{25}+\frac{3}{25}\cdot\frac{7}{11}-\frac{14}{25}\cdot\frac{7}{11}\)

\(=9\frac{7}{25}+\frac{7}{11}\cdot\left(\frac{3}{25}-\frac{14}{25}\right)\)

\(=9\frac{7}{25}+\frac{7}{11}\cdot\left(-\frac{11}{25}\right)\)

\(=9\frac{7}{25}+\left(-\frac{7}{25}\right)\)

\(=9\)

Chắc sai =]]

thank

a, 2/3 - 2/9 + 7/9 = 6/9 - 2/9 + 7/9 = 10/9
b, 7/6 + 3/5 : 6 = 7/6 + 3/5 x 1/6 = 7/6 + 1/10 = 70/60 + 6/10 = 76/10 = 38/5
c, x : 6/25 = 18

x = 18 x 6/25

x = 36/25
d, ( 2/5 + 4/7) : x = 17/5

29/35 : x = 17/5

x = 29/35 : 17/5

x = 29/119

\(a.\dfrac{2}{3}-\dfrac{2}{9}+\dfrac{7}{9}=\dfrac{6}{9}-\dfrac{2}{9}+\dfrac{7}{9}=\dfrac{4}{9}+\dfrac{7}{9}=\dfrac{11}{9}\\ b.\dfrac{7}{6}+\dfrac{3}{5}:6=\dfrac{7}{6}+\dfrac{3}{5}\times\dfrac{1}{6}=\dfrac{7}{6}+\dfrac{1}{10}=\dfrac{70}{60}+\dfrac{6}{60}=\dfrac{76}{60}=\dfrac{19}{15}\\ c.x:\dfrac{6}{25}=18\\ x=18\times\dfrac{6}{25}\\ x=\dfrac{108}{25}\\ d.\left(\dfrac{2}{5}+\dfrac{4}{7}\right):x=\dfrac{17}{5}\\ \dfrac{34}{35}:x=\dfrac{7}{5}\\ x=\dfrac{34}{35}:\dfrac{7}{5}\\ x=\dfrac{34}{49}\)

9-25=(7-x)-(25+7)

( 7 - x ) - ( 25 + 7 ) = 9 - 25

( 7 - x ) - 32 = - 16

     7 - x      = ( - 16 ) + 32 

      7 - x     = 16

           x     = 7 - 16

           x     = - 9

Vậy x = - 9 

9 - 25 = ( 7 - x ) - ( 25 + 7 )

x = 7 - 25 - 7 - 9 + 25

x = ( 7 - 7 ) + ( 25 - 25 ) -9

x =  0  + 0 - 9

x= - 9

=> x= - 9 

Vậy x = - 9

tớ chỉ làm được phần a)thôi

ta có:\(\left(x-\frac{2}{3}\right):\frac{-3}{7}=\frac{-9}{11}\)

\(x-\frac{2}{3}=\frac{-9}{11}.\frac{-3}{7}\)

\(x-\frac{2}{3}=\frac{27}{77}\)

\(x=\frac{27}{77}+\frac{2}{3}\)

\(x=\frac{235}{231}\)

vậy x=\(\frac{235}{231}\)

a) \(\left(x-\frac{2}{3}\right)\):\(\frac{-3}{7}\)=\(\frac{-9}{1}\)

                        \(x-\frac{2}{3}\)=\(-9\cdot\frac{-3}{7}\)

                        \(x-\frac{2}{3}\)= \(\frac{27}{7}\)

                                     \(x\)= \(\frac{27}{7}\)\(+\frac{2}{3}\)

                                      \(x\)=\(\frac{95}{21}\)

b)\(x:2+x:\frac{5}{2}+x:\frac{1}{3}=\frac{-18}{25}\)

      \(x:\left(2+\frac{5}{2}+\frac{1}{3}\right)=\frac{-18}{25}\)

            \(x:\frac{12+15+2}{6}=\frac{-18}{25}\)

                                \(x:\frac{29}{6}=\frac{-18}{25}\)

                                          \(x=\frac{-18}{25}\cdot\frac{29}{6}\)

                                           \(x=\frac{-87}{25}\)

114 nhé

(x + 7) : 5 =25 (dư 4)

(x + 7)      =25 * 5 (dư 4)

(x + 7)      =125 (dư 4)

x               =125 - 7 (dư 4)

x               =118 (dư 4)

x               =118 + 4

x               =122

Cách làm : 25 x 5 = 125 - 7 = 118 

Đáp số : 118 

Học tốt

a,- 25/18

b,79/25

làm đầy đủ nhé bn

A- 25/18

=77.

TK MK NHA. BẠN HỨA RỒI MÀ

Bằng 77 nha bạn 

0-(-77)=77