tính giá trị biểu thức (1/6+1/10+1/15) :(1/6+1/10-1/15)

( $\dfrac{1}{6}$ + $\dfrac{1}{10}$ + $\dfrac{1}{15}$ ) : ( $\dfrac{1}{6}$ + $\dfrac{1}{10}$ - $\dfrac{1}{15}$ )

=( $\dfrac{5}{30}$ + $\dfrac{3}{30}$ + $\dfrac{2}{30}$ ) : ( $\dfrac{5}{30}$ + $\dfrac{3}{30}$ - $\dfrac{2}{30}$ ) $\dfrac{1}{15}$ )

= $\dfrac{10}{30}$ : $\dfrac{6}{30}$

=$\dfrac{300}{180}$ = $\dfrac{5}{3}$ 

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