Question

[Triều Nguyễn Quốc]

1.Tính:

a; 0,25 x 2\(\dfrac{1}{3}\) x 30 x 0,5 x \(\dfrac{8}{45}\)

b; \(\dfrac{7}{12}\) + \(\dfrac{5}{12}\) : 6 + \(\dfrac{11}{36}\)

2.Tìm x :

( \(\dfrac{242}{363}\) + \(\dfrac{1616}{2121}\) ) = \(\dfrac{2}{7}\) . x

giúp mình nhé

Answer 1

[thám tử]

1.

a. 0,25 . \(2\dfrac{1}{3}\) .30 .0,5 . \(\dfrac{8}{45}\)

= \(\dfrac{1}{4}.\dfrac{7}{3}.30.\dfrac{1}{2}.\dfrac{8}{45}\)

= \(\dfrac{14}{9}\)

b. \(\dfrac{7}{12}+\dfrac{5}{12}:6+\dfrac{11}{36}\)

= \(\dfrac{7}{12}+\dfrac{5}{72}+\dfrac{11}{36}\)

= \(\dfrac{42}{72}+\dfrac{5}{72}+\dfrac{22}{72}\)

= \(\dfrac{23}{24}\)

2.

\(\left(\dfrac{242}{363}+\dfrac{1616}{2121}=\right)\dfrac{2}{7}.x\)

\(\dfrac{10}{7}=\dfrac{2}{7}.x\)

=> \(\dfrac{2}{7}.x=\dfrac{10}{7}\)

\(x=\dfrac{10}{7}:\dfrac{2}{7}\)

\(x=5\)