Question

Tìm X : 

a. X x 2/⁵ = 2 4/⁷   

b. X x 26 = 7,8 x 34     

( X in hoa là X, còn x thường là dấu nhân nha mọi người )

Answer 1

`x xx 2/5 = 2 4/7`

`x xx 2/5 = 18/7`

`x=18/7:2/5`

`x=18/7xx5/2`

`x=45/7`

__

`x xx 26=7,8xx34`

`x xx 26 =265,2`

`x=265,2:26`

`x=10,2`

Answer 2

\(a,x\times\dfrac{2}{5}=2\dfrac{4}{7}\\ x\times\dfrac{2}{5}=\dfrac{18}{7}\\ x=\dfrac{18}{7}:\dfrac{2}{5}\\ x=\dfrac{45}{7}\\ b,x\times26=7,8\times34\\ x\times26=265,2\\ x=265,2:26\\ x=10,2\)

Answer 3

\(a,x\times\dfrac{2}{5}=2\dfrac{4}{7}\\ =>x\times\dfrac{2}{5}=\dfrac{18}{7}\\ =>x=\dfrac{18}{7}:\dfrac{2}{5}\\ =>x=\dfrac{18}{7}\times\dfrac{5}{2}\\ =>x=\dfrac{45}{7}\)

Vậy \(x=\dfrac{45}{7}\)

\(b,x\times26=7,8\times34\\ =>x\times26=\dfrac{39}{5}\times34\\ =>x\times26=\dfrac{1326}{5}\\ =>x=\dfrac{1326}{5}:26\\ =>x=\dfrac{51}{5}\)

Vậy \(x=\dfrac{51}{5}\)

Answer 4

`a,`

`x xx 2/5 = 2 4/7`

`=> x xx 2/5 = (2xx7+4)/7`

`=>  x xx 2/5 = 18/7`

`=>x=18/7 : 2/5`

`=> x=18/7 xx 5/2`

`=>x= 90/14`

`=>x= 45/7`

`b,`

`x xx 26 = 7,8 xx 34`

`=> x xx 26 =265,2`

`=> x= 265,2 : 26`

`=>x= 10,2`