4/10 = - X - 4/10

- X   = 4/10 + 4/10

- X = 4/5

X  = -4/5

\(\frac{4}{10}=-x-\frac{4}{10}\)

                \(x=-\frac{4}{10}-\frac{4}{10}\)

                \(x=-\frac{4}{5}\)

B nha em

Chọn B

\(\left(x+4\right)\left(2-x\right)+x\left(x+2\right)=10\\ \Leftrightarrow-x^2+2x-4x+8+x^2+2x=10\\ \Leftrightarrow x^2-x^2+2x-4x+2x=10-8\\ \Leftrightarrow0x=-2\left(vô.lí\right)\\ Không.có.x.thoả.mãn\)

\(\left(x+3\right)\cdot10=\left(x-4\right)\cdot5\)

\(\Rightarrow\) \(10x+30=5x-20\)

\(\Rightarrow\) \(10x-5x=-20-30\)

\(\Rightarrow\) \(5x=-50\)

\(\Rightarrow\) \(x=-50\div5\)

\(\Rightarrow\) \(x=-10\)

( x + 3 ) x 10 = ( x - 4 ) x 5

10x + 30 = 5x - 20

10x - 5x = - 30 - 20

5x = - 50

x = - 50 : 5

x = - 10

\(\left(x+3\right).10=\left(x-4\right).5\)

\(\left(x+3\right).2=x-4\)   ( chia cả 2 vế cho \(5\))

\(2x+6=x-4\)

\(2x-x=-4-6\)

\(x=-10\)

vậy \(x=-10\)

4 ( x- 1 0 ) - 3 ( 5 +x ) + 2 ( 4x- 3 ) = 5.  ( x- 2 )

4x - 40 - 15 - 3x + 8x - 6 = 5x - 10

4x - 3x + 8x - 5x            = -10 + 40 + 15 + 6 

4x                                =  51

x                                  = 51/4 

tick đúng cho mình nha 

(x+1)+(x+4)+(x+7)+(x+10)=62

=>4x+22=62

=>4x=62-22

=>4x=40

=>x=10

t tôi nha bn

x+(1+4+7+10)=62

x+22=62

x=62-22

x=40

( x + 1 ) + ( x + 4 ) + ( x + 7 ) + ( x + 10 ) = 62

4x+ (1+4+7+10)=62

4x+22=62

4x=62-22

4x=40

x=40:4

x=10

` (3/4 +x) xx 50/100 = 8/10`

`( 3/4 + x) xx 1/2 = 4/5`

` 3/4 + x = 4/5 : 1/2`

` 3/4 + x = 4/5 xx2`

` 3/4 + x = 8/5`

` x = 8/5 - 3/4`

` x = 17/20`

Tìm x, biết:

( 3/4 + x ) x 50/100 = 8/10

( 3/4 + x ) = 8/10 : 50/100

( 3/4 + x ) = 8/5

x = 8/5 - 3/4

x = 17/20.

=>x+3/4=4/5:1/2=4/5x2=8/5

=>x=8/5-3/4=32/20-15/20=17/20

x=1