18 . [(8x + 10 ) : 5] + 12 = 490 

        18 . [(8x + 10 ) : 5]    = 490 - 12

        18 . [(8x + 10 ) : 5]    = 478

              [(8x + 10 ) : 5]    = 478 : 18 

               ( 8x + 10 ) : 5    = \(\frac{239}{9}\)

                 8x + 10           =     \(\frac{239}{9}\)  .5

                 8x + 10           = \(\frac{1195}{9}\)

                         8x           = \(\frac{1195}{9}\) - 10 

                         8x           = \(\frac{1195}{9}-\frac{90}{9}\)

                         8x           = \(\frac{1105}{9}\)

                            x          = \(\frac{1105}{9}\)\(\div\)8

                            x          =   \(\frac{1105}{9}\) . \(\frac{1}{8}\)

                            x          = \(\frac{1105}{72}\)

\(\Rightarrow\frac{x+10}{490}+\frac{x+20}{480}+\frac{x+30}{470}+\frac{x+40}{460}+\frac{x+50}{450}+5=0\)

\(\Rightarrow\frac{x+10}{490}+1+\frac{x+20}{480}+1+\frac{x+30}{470}+1+\frac{x+40}{460}+1+\frac{x+50}{450}+1=0\)

\(\Rightarrow\frac{x+500}{490}+\frac{x+500}{480}+\frac{x+500}{470}+\frac{x+500}{460}+\frac{x+500}{450}=0\)

\(\Rightarrow\left(x+500\right).\left(\frac{1}{490}+\frac{1}{480}+\frac{1}{470}+\frac{1}{460}+\frac{1}{450}\right)=0\Rightarrow x+500=0\Rightarrow x=-500\)

Khó Lazy kute

Biết khó mới hỏi ! Câu dễ thì tớ gửi cho zui thui !!!!!!!!

882:(2x-15)=18

2x-15=882:18

2x-15=49

2x=49+15

2x=64

x=32

k mk nha

mk nhanh nhất

882;(2.x-15)=18

2.x-15=822:18=49

2.x=49+15=64

x=64:2=32

\(1) 420+65.4=(x+175):5+30\)

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

\(\implies 680=(x+175):5+30\)

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

\(\implies 650.5-175=x\)

\(\implies 3075=x\)

\(2)x-4867=(175.2050.70):25+23\)

\(\implies x-4867=1004500+23\)

\(\implies x-4867=1004523\)

\(\implies x=1009390\)

\(3) 134-[(96-7x):4-2]=126\)

\(\implies (96-7x):4-2=8\)

\(\implies(96-7x):4=10\)

\(\implies 96-7x=40\)

\(\implies 7x=56\)

\(\implies x=8\)

\(4) 4-\{100-[(100-5x):8-5]:10\}:25=0\)

\(\implies 4-\{100-[(100-5x):8-5]:10\}=0\)

\(\implies 100-[(100-5x):8-5]:10=4\)

\(\implies 100-[(100-5x):8-5]=40\)

\(\implies (100-5x):8-5=60\)

\(\implies (100-5x):8=65\)

\(\implies 100-5x=520\)

\(\implies 5x=-420\)

\(\implies x=-84\)

~ Hok tốt a~

ai nua cac ban

ban nao biet thi minh h

a) 10*(x-1)=15-5

10*(x-1)=10

(x-1)=10:10

(x-1)=1

x=1+1

x=2 

b) x+1+x+2+x+3=18

3x+6=18

3x=18-6

3x=12

x=12:3

x=4

c) 17+2*(x+2)=25

2*(x+2)=25-17

2*(x+2)=8

x+2=8:2

x+2=4

x=4-2

x=2

d) x:17=82-17+26

x:17=91

x=91*17

x=1547

e) 147*x=441

x=441:147

x=3

g)(x:81)=330:10:11

(x:81)=3

x=3*81

x=243

i)x+1+x+2+x+3+x+4+x+5=40

5x+15=40

5x=40-15

5x=25

x=5

Ủng hộ nha 

bạn làm sao ấy đề mink viet khac ma ban vite mot neo

thiếu bạn ak

\(\left(117+30\right)\cdot x=882:2\)

\(147\cdot x=441\)

\(x=441:147\)

\(x=3.\)

ko hieu left viet cho dung ra so luon di

(117+30)*x=882:2

147 * x = 441

x = 441 : 147

x = 3