a) 86 – 16 = 70 

b) 23 x 2 – 1 = 23 

c) 250 : 5 + 5 = 25 

d) 40 + 80 : 4 = 30 

e) 80 + 4 : 2 = 42 

f) 70 + 30 : 2 = 50 

g) 90 + 30 x 3 = 180 

h) 70 + 30 : 2 = 85 

300

300

= 300 

420 + 65 . 4 = ( x + 175 ) : 5 + 30 

=> ( x + 175 ) : 5 + 30 = 420 + 45 . 4 

=> ( x + 175 ) : 5 + 30 = 600 

=> ( x + 175 ) : 5 = 600 - 30 

=> ( x + 175 ) : 5 = 570 

=> x + 175 = 570 . 5 

=> x + 175 = 2850 

=> x = 2850 - 175 

=> x = 2675 

nha bn 

các câu khác tương tự nhé 

nhớ ủng hộ mik nha mn 

\(\text{Tìm x hở e????}\)

~~~~~~~~~

\(\text{420 + 65 . 4 = ( x + 175 ) : 5 + 30}\)

\(420+260=\left(x+175\right):5+30\)

\(680=\text{ ( x + 175 ) : 5 + 30}\)

\(\text{ ( x + 175 ) : 5 + 30=680}\)

\(\text{ ( x + 175 ) : 5 =680-30}\)

\((x+175):5=650\)

\(x+175=650:5\)

\(x+175=130\)

\(x=130-175\)

\(x=-45\)

\(\text{(32.15) : 2 = (x + 70) : 14 - 40}\)

\(480:2=\text{ (x + 70) : 14 - 40}\)

\(240\text{ = (x + 70) : 14 - 40}\)

\(\text{ (x + 70) : 14 =280}\)

\(x+70=3920\)

\(x=3920-70\)

\(x=3850\)

\(\text{x - 4867 = ( 175 . 2050 . 76) + 25 + 23}\)

\(\text{x - 4867 = ( 175 . 2050 . 76) + 48}\)

\(x-4867=27265000+48\)

\(x-4867=27265048\)

\(x=27265048+4867\)

\(x=27260015\)

\(\text{Hok giỏi nhé!~!!}\)

a, \(420+65:4=\left(x+175\right):5+30\)

\(\Rightarrow\left(x+175\right):5+30=420+16,25\)

\(\Rightarrow\left(x+175\right):5=420+16,25-30=406,25\)

\(\Rightarrow x+175=2031,25\)

\(\Rightarrow x=1856,25\)

b, \(\left(32.15\right):2=\left(x+70\right):14-40\)

\(\Rightarrow\left(x+70\right):14-40=480:2\)

\(\Rightarrow\left(x+70\right):14=240+40=280\)

\(\Rightarrow x+70=3920\Rightarrow x=3850\)

c, \(x-4867=\left(175.2050.70\right):25+23\)

\(\Rightarrow x=39462500:25+23+4867\)

\(\Rightarrow x=1578500+23+4867=1583390\)

Chúc bạn học tốt!!!

* \(20+65.4=\left(x+75\right):5+30\)

\(\Leftrightarrow20+260-30=\frac{x}{5}+\frac{75}{5}\)

\(\Leftrightarrow20+260-30-\frac{75}{5}=\frac{x}{5}\)

\(\Leftrightarrow235=\frac{x}{5}\Rightarrow x=235.5=1175\)

* \(2248:\left[119-\left(x-6\right)\right]=24\)

\(\Leftrightarrow2248:\left(119-x+6\right)=24\)

\(\Leftrightarrow2248:\left(125-x\right)=24\)

A mình lỡ tay, để mình tính tiếp nhá!

\(\Leftrightarrow125-x=2248:24\Leftrightarrow125-x=\frac{281}{3}\Rightarrow-x=\frac{94}{3}\Rightarrow x=-\frac{94}{3}\)(bài này mình thấy sai sai sao á, nếu mình làm sai thì thông cảm cho mình nhé!

* \(\left(x+70\right):14-40=\left(32.15\right):2\)

\(\Leftrightarrow\left(x+70\right):14=480:2+40\)

\(\Leftrightarrow\frac{x}{14}+5=280\Leftrightarrow\frac{x}{14}=275\Rightarrow x=3850\)

* \(x-4867=\left(175.2050.70\right):25+23\)

\(\Leftrightarrow x-4867-23=\left(175:25\right).\left(2050:25\right).\left(70:25\right)\)

\(\Leftrightarrow x-4890=7.82.\frac{14}{5}\)

\(\Leftrightarrow x-4890=\frac{8036}{5}\Rightarrow x=\frac{8036}{5}+4890=\frac{32486}{5}\)(bài này mình thấy hình như cũng có cái gì đó sai sai luôn hihi!)

=24 nha

Lời giải chi tiết:

2-4+6-8+10-12+14-16+18-20+22

=(2+18)-(4+16)+(6+14)-(8+12)-(10+20)+22

=20-20+20-20-20+22

=22-20

=2

1999-2000+2999-3000+3999-4000+4999-5000+5999-1000

=(1999-1000)+(2999-2000)+(3999-3000)+(4999-4000)+(5999-5000)

=999x5

=4995

2-4+6-8+10-12+14-16+18-20+22                                                                                                                                                            =2+(6-4)+(10-8)+(14-12)+(18-16)+(22-20)                                                                                                                                                            = 2+2+2+2+2+2                                                                                                                                                             = 12

a)13-2(x+1)=7

  2.(x+1)=13-7

  2.(x+1)=6

  x+1=6/2

  x+1=3 

  x=3-1

  x=2

a, 13 - 2 ( x + 1 ) = 7

          2 .( x + 1 ) = 13 - 7
          2 .( x + 1 ) = 6
                x + 1   = 6 : 2
                x + 1    = 3
                x          = 3 - 1
                x           = 4

b)6x+2.4=5².2

6x+2=50

6x=48

x=8

c)420+65.4=(x+175):5+30

(x+175):5+30=680

(x+175):5=650

x+175=3250

x=3075