Toán Lớp 5: e) X x`7/9` = `2/3 + `5/4` g) X – `7/9` =`2/3` : `6/5` h) `1/4` +`9/8` : X =`1/2` i)`5/7` + X :`9/4` = `4/3`

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1.               #Fan Elaina

   e, x × $\frac{7}{9}$ =$\frac{2}{3}$ + $\frac{5}{4}$ 

       x × $\frac{7}{9}$ =$\frac{23}{12}$

       x =$\frac{23}{12}$ : $\frac{7}{9}$ 

       x = $\frac{69}{28}$ 

    ———-

   g, x – $\frac{7}{9}$ = $\frac{2}{3}$ : $\frac{6}{5}$

       x – $\frac{7}{9}$ = $\frac{5}{9}$

       x = $\frac{5}{9}$ + $\frac{7}{9}$

       x = $\frac{4}{3}$ 

   ———-

   h, $\frac{1}{4}$ + $\frac{9}{8}$ : x = $\frac{1}{2}$

       $\frac{9}{8}$ : x = $\frac{1}{2}$ – $\frac{1}{4}$

       $\frac{9}{8}$ : x = $\frac{1}{4}$

       x = $\frac{9}{8}$ : $\frac{1}{4}$

       x = $\frac{9}{2}$

   ———-

   i, $\frac{5}{7}$ + x : $\frac{9}{4}$ = $\frac{4}{3}$ 
      x : $\frac{9}{4}$ = $\frac{4}{3}$ – $\frac{5}{7}$ 
      x : $\frac{9}{4}$ = $\frac{13}{21}$ 
      x = $\frac{13}{21}$ . $\frac{9}{4}$ 
      x = $\frac{39}{28}$ 

   Trả lời
2. Lời giải và giải thích chi tiết:

   e)

   x × 7/9 = 2/3 + 5/4

   x × 7/9 = 13/6

   x = 13/6 : 7/9 = 39/14

   g)

   x – 7/9 = 2/3 : 6/5

   x – 7/9 = 5/9

   x = 12/9

   x = 4/3

   h)

   1/4 + 9/8 : x = 1/2

   9/8 : x = 1/4

   x = 9/8 : 1/4 = 9/2

   i)

   5/7 + x : 9/4 = 4/3

   x : 9/4 = 4/3 – 5/7 = 13/21

   x = 13/21 × 9/4 = 117/84

   Trả lời