a)17.65+17.35-x=1570

17.(65+35)-x=1570

17.100-x=1570

1700-x=1570

x=1700-1570=130

b)x+16.14+9.4=7.9.12+63.88

  x+224+36=756+5544

  x+260      =6300

  x=6300-260=6040

c)x.2^3=2^6

   x      =2^6:2^3

   x      =2^3=8

Từ -5:(1-x)=7:(-3)

=>\(\dfrac{-5}{1-x}=\dfrac{7}{-3}\)=>7.(1-x)=-5.(-3)

=>7-7x=15

=>7x=7-15=-8

=>x=\(\dfrac{-8}{7}\)

\(3\cdot\left(x-2\right)^2=2+25\)

\(\Leftrightarrow3\cdot\left(x-2\right)^2=27\)

\(\Leftrightarrow\left(x-2\right)^2=9\)

\(\Leftrightarrow\orbr{\begin{cases}x-2=3\\x-2=-3\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=5\\x=-1\end{cases}}\)

\(\frac{x}{2}+x+\frac{x}{3}+x+x+\frac{x}{4}=\frac{23}{12}\)

\(\left(\frac{x}{2}+\frac{x}{3}+\frac{x}{4}\right)+\left(x+x+x\right)=\frac{23}{12}\)

\(\frac{3x}{12}+\frac{36x}{12}=\frac{23}{12}\)

\(\frac{49x}{12}=\frac{23}{12}\)

\(\frac{49}{12}.x=\frac{23}{12}\)

          \(x=\frac{23}{12}:\frac{49}{12}=\frac{23}{49}\)

Ta có (x+2)³ = (x+2)²

=> x+2=1 nên x=-1    hoặc   x+2=0 nên x=-2

ko bik đúng hay sai!!!!!!!!!!!!!!!!!!!!! 

Ta có : \(\left(x+1\right)+\left(x+3\right)+\left(x+5\right)+\left(x+7\right)=32\)

         \(\Leftrightarrow x+x+x+x+1+3+5+7=32\)

          \(\Leftrightarrow4x+16=32\Leftrightarrow4x=16\Leftrightarrow x=4.\)

\(\left(x+1\right)+\left(x+3\right)+\left(x+5\right)+\left(x+7\right)=32\)

\(\left(x+x+x+x\right)+\left(1+3+5+7\right)=32\)

\(4x+16=32\)

\(4x=16\)

\(\Leftrightarrow x=4\)

(x+1)+(x+3)+(x+5)+(x+7)=32

=> x+1+x+3+x+5+x+7     =32

=> 4x + 16                       = 32

=> 4x                                = 32-16

=> 4x                                = 16

=> x                                   = 4

Vậy x=4

x/49=-2/7

=> 7x=-2.49

=>7x=-98

=>x=-14

so easy

Gọi A,B là hai điểm trên tia Ox. Biết OA=8cm,AB=2cm. Tính OB. Bài toán có mấy đáp số.
 

|-3|+|-7|=x+3

3+7=x+3

\(\Rightarrow\)x=7

⇒ x = 2

X - 7 = 5

X    =7+5

X     = 12