Question

Tính : 

(9/4x-0,5): 1  3/4 =1
7/x=x/28

Answer 1

: 1  3/4  là sao ak ??

Answer 2

\(\left(\dfrac{9}{4}x-0,5\right):1\dfrac{3}{4}=1\)

\(\left(\dfrac{9}{4}x-0,5\right):\dfrac{7}{4}=1\)

\(\dfrac{9}{4}x-0,5=1.\dfrac{7}{4}\)

\(\dfrac{9}{4}x-0,5=\dfrac{7}{4}\)

\(\dfrac{9}{4}x=\dfrac{7}{4}+0,5\)

\(\dfrac{9}{4}x=\dfrac{7}{4}+\dfrac{1}{2}\)

\(\dfrac{9}{4}x=\dfrac{9}{4}\)

\(x=\dfrac{9}{4}:\dfrac{9}{4}\)

\(x=1\)

 

`7/x = x/28`

`x.x = 7 xx 28`

` x.x = 196`

` x^2 = 196`

` -> x = 14`

Vậy `x = 14`

Answer 3

 

 

 

 

7/x=x/28

=> x.x=7.28

=> x^2 =196

=> x^2 = 14^2

=> x= 14 
     x= -14

Vay x ∈ { 14, -14 } 

Answer 4

\(\left(\dfrac{9}{4}x-0,5\right):\dfrac{7}{4}=1\\ \left(\dfrac{9}{4}x-0,5\right)=1.\dfrac{7}{4}\\ \left(\dfrac{9}{4}x-0,5\right)=\dfrac{7}{4}\\ \dfrac{9}{4}x=\dfrac{7}{4}+0,5\\ \dfrac{9}{4}x=\dfrac{9}{4}\\ x=1\)

\(b,\dfrac{7}{x}=\dfrac{x}{28}\\ 7.28=x.x\\ 196=x^2\\ \left[\begin{matrix}x=14\\x=-14\end{matrix}\right]\)