3*y*(1/4*7+1/7*10+1/10*13+1/13*16)=1/13-1/16 * là nhân nha

0 bình luận về “3*y*(1/4*7+1/7*10+1/10*13+1/13*16)=1/13-1/16 * là nhân nha”

1. 3 × y × ($\frac{1}{4×7}$ + $\frac{1}{7×10}$ + $\frac{1}{10×13}$ + $\frac{1}{13×16}$) = $\frac{1}{13}$ – $\frac{1}{16}$

   y × ($\frac{3}{4×7}$ + $\frac{3}{7×10}$ + $\frac{3}{10×13}$ + $\frac{3}{13×16}$) = $\frac{1}{13}$ – $\frac{1}{16}$

   y × ($\frac{1}{4}$ – $\frac{1}{7}$ + $\frac{1}{7}$ – $\frac{1}{10}$ + $\frac{1}{10}$ – $\frac{1}{13}$ + $\frac{1}{13}$ – $\frac{1}{16}$) =  $\frac{1}{13}$ – $\frac{1}{16}$

   y × ($\frac{1}{4}$ – $\frac{1}{16}$) =  $\frac{1}{13}$ – $\frac{1}{16}$

   y × ($\frac{4-1}{16}$) = $\frac{16-13}{208}$ 

   y × $\frac{3}{16}$ = $\frac{3}{208}$

   y = $\frac{3}{208}$ : $\frac{3}{16}$  

   y = $\frac{3}{208}$ × $\frac{16}{3}$

   y = $\frac{1}{13}$

   Chúc bạn học tốt ^^ 

    

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2. Đáp án:   `y = 1/13`

   Giải thích các bước giải:

   `3 xx y xx ( 1/(4.7) + 1/(7.10) + 1/(10.13) + 1/(13.16) ) = 1/13 – 1/16`

   `3 xx y xx 1/3 . ( 3/(4.7) + 3/(7.10) + 3/(10.13) + 3/(13.16) ) = 16/208 – 13/208`

   `y xx ( 1/4 – 1/7 + 1/7 – 1/10 + 1/10 – 1/13 + 1/13 – 1/16 ) = 3/208`

   `y xx ( 1/4 – 1/16 ) = 3/208`

   `y xx ( 4/16 – 1/16 ) = 3/208`

   `y xx 3/16 = 3/208`

   `y = 3/208 : 3/16`

   `y = 3/208 . 16/3`

   `y = 1/13`

    

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