Bài 5.
a. 9/17 . 2/7 + 9/17 : 7/4
=\(\dfrac{\left(\dfrac{9}{17}.\dfrac{3}{7}+\dfrac{9}{17}.4\right)}{7}=\dfrac{\dfrac{360}{119}}{7}=\dfrac{360}{119.7}=\dfrac{360}{833.}\)
b. ( -9/25) .17 \(\dfrac{2}{3}\) - (-3/5)^2 . 22/3
= -9/25 . 53/3 - (-3/5)^2 . 22/3= -159/25 - 66/25= -9
c. 6/7 . 8/13 + 6/13 . 9/7 - 4/13 . 6/7
= 48/91 + 54/91 - 24/91= 78/91= 6/7.
d.
(67/111 + 2/33 - 11/117)(1/3 - 25% - 1/12)= 0
= (67/111 + 2/33 - 5/39)(1/3 - 1/4 - 1/12)
= 2836/5291 . 0= 0.
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