Xx1/2+45=Xx2 -45

Xx(2-1/2)-45=45

Xx3/2=45+45

Xx3/2=90

X=90:3/2

X=60

Em viết công thức toán bị lỗi rồi.

`x/2 + x xx 2 = 2/5`

`=> 5/2 xx x  = 2/5`

`=>` `x= 4/25`

=>5/2x=2/5

hay x=2/5:5/2=4/25

x=4/25

x\(.\frac{2}{7}-\frac{2}{3}=\frac{1}{2}\)

= \(x.\frac{2}{7}=\frac{1}{2}+\frac{2}{3}\)

\(=x.\frac{2}{7}=\frac{7}{6}\)

\(x=\frac{7}{6}:\frac{2}{7}\)

x = \(\frac{49}{12}\)

xchia 5/4+4/5=2

\(x.\frac{2}{7}-\frac{2}{3}=\frac{1}{2}\)

\(\Rightarrow x.\frac{2}{7}=\frac{1}{2}+\frac{2}{3}\)

\(\Rightarrow x.\frac{2}{7}=\frac{7}{6}\)

\(\Rightarrow x=\frac{7}{6}:\frac{2}{7}\)

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

- Với mọi x > 2 ta có :

- Do đó:

Vậy chọn đáp án C

chọn đáp án A

Với mọi x> 2 ta có 

Do đó

ĐKXĐ: -2x+1>=0

=>-2x>=-1

=>x<=1/2

x - x * 2 + x * 2 - 2 - 3 = 0

x - 2 = 0 + 3

x - 2 = 3

x = 3 + 2

x = 5

X + X x 2 + X x 2 - 2 - 3 = 0

X + X x 2 + X x 2 = 0 + 3 + 2 = 5

X x 1 + X x 2 + X x 2 = 5

X x (1 + 2 + 2) = 5

X x 5 = 5

X = 5 : 5

X = 1

Nhầm làm lại nha !

x + x * 2 + x * 2 - 2 - 3 = 0

x * 3 + x * 2 - 5 = 0

x * 5 - 5 = 0

x * 5 = 0 + 5

x * 5 = 5

x = 5 : 5

x = 1

\(3-\left(2x+\frac{1}{2}\right)\div\frac{1}{2}=2\)

\(\Leftrightarrow\left(2x+\frac{1}{2}\right)\div\frac{1}{2}=3-2\)

\(\Leftrightarrow\left(2x+\frac{1}{2}\right)\times2=1\)

\(\Leftrightarrow2x+\frac{1}{2}=\frac{1}{2}\)

\(\Leftrightarrow2x=\frac{1}{2}-\frac{1}{2}\)

\(\Leftrightarrow2x=0\)

\(\Leftrightarrow x=0\div2\)

\(\Leftrightarrow x=0\)

Vậy x = 0

\(3-\left(x\times2+\frac{1}{2}\right):\frac{1}{2}=2\)

         \(\left(x\times2+\frac{1}{2}\right):\frac{1}{2}=3-2\)

         \(\left(x\times2+\frac{1}{2}\right):\frac{1}{2}=1\)

                      \(x\times2+\frac{1}{2}=1\times\frac{1}{2}\)

                      \(x\times2+\frac{1}{2}=\frac{1}{2}\)

                                  \(x\times2=\frac{1}{2}-\frac{1}{2}\)

                                  \(x\times2=0\)

                                              x = 0 : 2

                                              x = 0

Vậy x = 0

x = 0

k mk nha ! Cảm ơn