x + 125 = 266

x = 266 - 125

x = 141

`#040911`

`a)`

`6 \times x - 5 = 613`

`=> 6 \times x = 613 + 5`

`=> 6 \times x = 618`

`=> x = 618 \div 6`

`=> x = 103`

Vậy, `x = 103`

`b)`

`12 \times x + 3 \times x = 30`

`=> x \times (12 + 3) = 30`

`=> x \times 15 = 30`

`=> x = 30 \div 15`

`=> x = 2`

Vậy, `x = 2`

`c)`

`125 - 25 \times (x - 1) = 100`

`=> 25 \times (x - 1) = 125 - 100`

`=> 25 \times (x - 1) = 25`

`=> x - 1 = 25 \div 25`

`=> x - 1 = 1`

`=> x = 1 + 1`

`=> x = 2`

Vậy, `x = 2`

`d)`

`(x - 2) \times (9x - 4) = 0?`

`=>`

TH1: `x - 2 = 0`

`=> x = 0 + 2`

`=> x = 2`

TH2: `9x - 4 = 0`

`=> 9x = 4`

`=> x = 4/9`

Vậy, `x \in {2; 4/9}.`

\(a,6x-5=613\\ \Leftrightarrow6x=618\\ \Leftrightarrow x=103\\ b,12x+3x=30\\ \Leftrightarrow15x=30\\ \Leftrightarrow x=2\\ c,125-25\left(x-1\right)=100\\ \Leftrightarrow25\left(x-1\right)=25\\ \Leftrightarrow x-1=1\\ \Leftrightarrow x=2\\ d,\left(x-2\right)\cdot\left(9x-4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{4}{9}\end{matrix}\right.\)

1.a) 4.(12+88) = 4.100=400

b)7²- 6 .[2.8:8 ]=7²-6.[16:8]=7²-6 .2= 49-12=37  ( tui ko chắc lắm )

2.a) x=26-11=15 

b) (4x-15)³=5³ 

4x-15=5 

4x= 5+15

4x=20

vậy x = 20

Bài 2: 

a: Ta có: x+11=26

nên x=15

b: Ta có: \(\left(4x-15\right)^3=125\)

\(\Leftrightarrow4x-15=5\)

hay x=5

125-30-x-125=x-237-8+237

-30-x=x-8

=> -30=2x-8

=> x=-11

a,x=10

b,x=89

a: Ta có: 7x+55=125

\(\Leftrightarrow7x=70\)

hay x=10

b: Ta có: \(55-\left(19-x\right)=125\)

\(\Leftrightarrow55-19+x=125\)

hay x=89

a) x + 125 = 999

    x              = 999 - 125 

x                  = 874

b) x- 125 = 999

x               = 999 + 125

x                = 1124

125-(30+x+125)=(x-237).[8+(-237)]

125-(30+x+125)=(x-237)×(-229)

125-(30+x+125)=x-237×(-229)

125-(30+x+125)=x-(-54273)

125-(30+x+125)=x+54273

125-30+x+125=x+54273

125-39+x=x+54273-125

125-39+x=x+54148

125-x=x+54148-39

125-x=x+54109

125-1x=1x+54109

125-1x=0

1x=125-0

1x=125

x=125÷1

x=125

dung nhung dai

\(125:x=125\times x\)

\(125\times\frac{1}{x}=125\times x\)

\(125\times\frac{1}{x}-125\times x=0\)

\(125\times\left(\frac{1}{x}-x\right)=0\)

\(\frac{1}{x}-x=0\)

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

\(\Rightarrow x=1\)

CHÚC BN HỌC TỐT!!

125:x = 125 × x 

125 × 1/x = 125 × x

125 ×  1/x - 125 × x

  125 × 1/x − x = 0 x 1 − x = 0 ⇒ x 1 = x ⇒x = 1

:3