sai đề rồi

\(x:2=x:3\\ \Rightarrow\dfrac{x}{2}-\dfrac{x}{3}=0\\ \Rightarrow\dfrac{3x-2x}{6}=0\\ \Rightarrow x=0\)

ko cs đáp án nha

bạn

Có: `C=34.51-14`

`=> C=34(50+1)-14`

`=> C=34.50+34-14`

`=> C=34.50+20<D=34.50+21`

   \(\dfrac{3}{5}\).\(\dfrac{7}{9}\) + \(\dfrac{3}{5}\).\(\dfrac{2}{9}\) + \(\dfrac{3}{5}\)

= \(\dfrac{3}{5}\).(\(\dfrac{7}{9}\)+ \(\dfrac{2}{9}\)+1)

= \(\dfrac{3}{5}\).(1+1)

= \(\dfrac{6}{5}\)

\(\dfrac{3}{5}\times\dfrac{7}{9}+\dfrac{3}{5}\times\dfrac{2}{9}+\dfrac{3}{5}=\dfrac{3}{5}\left(\dfrac{7}{9}+\dfrac{2}{9}+1\right)=\dfrac{3}{5}\times\left(\dfrac{9}{9}+1\right)=\dfrac{3}{5}\times\left(1+1\right)=\dfrac{3}{5}\times2=\dfrac{6}{5}\)

`-5/6+3x=2/3-1/3 x`

`=> 2/3+5/6=3x+1/3 x`

`=> 3/2=10/3 x`

`=> x=9/20`

`-5/6+3x=2/3-1/3x`

`3x+1/3x=2/3+5/6`

`(3+1/3)x=3/2`

`10/3x=3/2`

`x=3/2:10/3`

`x=9/20`

Vì x ϵ B₍₁₃₎ hay x ⋮ 13

Mà 12 < x < 80 nên x ϵ { 13 ; 26 ; 39 ; 52 ; 65 ; 78 }

(x+5)² = 4

x + 5 = +-2

X = -3;  -7

x= -3

Vì 123x43y ⋮ 5 ⇒ y = 0 hoặc 5

- Nếu y = 0 ⇒ 123x43y = 123x430 ⋮ 3

⇒ 1 + 2 + 3 + x + 4 + 3 + 0 ⋮ 3

⇒ 9 + x + 4 ⋮ 3 mà 9 ⋮ 3 ⇒ x + 4 ⋮ 3 

Vì 0 ≤ x ≤ 9 nên 4  ≤ x + 4 ≤ 13 mà x + 4 ⋮ 3 nên 

x + 4 = 6 ; 9 ; 12

Nếu x + 4 = 6 ⇒ x = 2

Nếu x + 4 = 9 ⇒ x = 5

Nếu x + 4 = 12 ⇒ x = 8

- Nếu y = 5 ⇒ 123x43y = 123x435 ⋮ 3

⇒ 1 + 2 + 3 + x + 4 + 3 + 5 ⋮ 3

⇒ 18 + x ⋮ 3 mà 18 ⋮ 3 nên x ⋮ 3

Vì 0 ≤ x ≤ 9 nên x = 0 ; 3 ; 6 ; 9

Vậy y = 0 thì x = 2; 5; 8   y = 5 thì x = 0 ; 3 ; 6 ; 9 

x=2(5;8;0)

y=0(5)