125 : x + 75 : x = 5

(125 + 75) : x = 5

200 : x = 5

x = 200 : 5

x = 40

125 : x + 75 : x = 5
(125 + 75) : x = 5
200 : x = 5
        x = 200 : 5
        x = 40

a) \(75:\left(x-2\right)+4=7\)

\(\Rightarrow75:\left(x-2\right)=7-4\)

\(\Rightarrow75:\left(x-2\right)=3\)

\(\Rightarrow x-2=75:3\)

\(\Rightarrow x-2=25\)

\(\Rightarrow x=27\)

b) \(125-3\left(x+3\right)=65\)

\(\Rightarrow3\left(x+3\right)=125-65\)

\(\Rightarrow3\left(x+3\right)=60\)

\(\Rightarrow x+3=60:3\)

\(\Rightarrow x+3=20\)

\(\Rightarrow x=17\)

a,\(75:\left(x-2\right)+4=7\\ \Rightarrow75:\left(x+2\right)=3\\ \Rightarrow x+2=25\\ \Rightarrow x=23.\)

b, \(125-3\left(x+3\right)=65\\ \Rightarrow3\left(x+3\right)=60\\ \Rightarrow x+3=20\\ \Rightarrow x=17.\)

X = 9380

x:125=75 dư 5

x       =75x125+5

x       =9380

\(A=\left|x-125\right|+\left|x+75\right|\)

\(A=\left|125-x\right|+\left|75+x\right|\)

Ta có: \(\hept{\begin{cases}\left|125-x\right|\ge125-x\\\left|75+x\right|\ge75+x\end{cases}\Rightarrow\left|125-x\right|+\left|x+75\right|\ge125-x+x+75=200}\)

\(A=200\Leftrightarrow\hept{\begin{cases}\left|125-x\right|=125-x\\\left|75+x\right|=75+x\end{cases}\Leftrightarrow\hept{\begin{cases}125-x\ge0\\75+x\ge0\end{cases}\Leftrightarrow}\hept{\begin{cases}x\le125\\x\ge-75\end{cases}\Rightarrow}-75\le x\le125}\)

Vậy \(A_{min}=200\Leftrightarrow75\le x\le125\)

Tham khảo nhé~

`5 xx 74 xx 2  = 5xx 2 xx 74 = 10xx74 = 740`

`4xx196xx5 = 4xx5xx196 = 20xx196 = 3920`

`(50 + 25)xx4 = 50xx4 + 25xx4 = 200 + 100 = 300`

`125xx(80+8) = 125xx80 + 125xx8 = 10000 + 1000 = 11000`

a) (y – 1) : 105 = 125 x 80

(y – 1) : 105 = 10000

(y – 1) = 10000 x 105

(y – 1) = 1050000

y = 1050000 + 1

y = 1050001

b) (y – 607 200) : 305 = 642 + 318

(y – 607 200) : 305 = 960

(y – 607 200) = 960 x 305

(y – 607 200) = 292800

y = 292800 + 607 200

y = 900000

\(a.\left(y-1\right):105=125x80\)                   \(b.\left(y-607200\right):305=642+318\)

\(\left(y-1\right):105=10000\)                             \(\left(y-607200\right):305=960\)

\(y-1=10000x105=1050000\)                \(y=960+607200=608160\)

\(y=1050000+1=1050001\)

\(c.\left(1780-973\right)x\left(75:y\right)=2401+20\)

\(807x\left(75:y\right)=2401+20\)

\(807x\left(75:y\right)=2421\)

\(75:y=2421:807=3\)

\(y=75:3=25\)

a.35 x 34 + 35 x 38 + 65 x 75 + 45 x 65

= 35 x (34 + 38) + 65 x 75 + 65 x 45

= 35 x     72      + 65 x (75+45)

= 35 x 72 + 65 x 120

= 35 x 72 + 65 x (72 + 48)

= 35 x 72 + 65 x 72 + 65 x 48

= (35+65) x 72 + 65  x 48

=   100 x 72 + 65 x 48

=      7200   +    3120

=           10320

b.39 x 8 + 60 x 2 + 21 x 8

=39 x 8 + 15 x 4 x 2 +21 x 8

= 39 x 8 + 15 x 8 + 21 x 8

=(39 + 15 + 21) x 8

=      75            x 8

=             600

c.58 x 75 + 58 x 50 - 58 + 25

= 58 x 75 + 58 x 50 - 58 x 1 + 25

= 58 x(75+50-1)+25

= 58 x   124     + 25

=    7192          + 25

=              7217

d.125 x 98 - 125 x 46 - 52 x 25

= 25 x 5 x 98 - 25 x 5 x 46 - 25 x 52

= 25 x 490 - 25 x 230 - 25 x 52

= 25 x (490 - 230 - 52)

= 25 x      208

=       5200

ham mo chi qua