Đáp án:
Ta có :
$ \dfrac{3}{4} × \dfrac{12}{7} + x = \dfrac{5}{2}$
$ <=> \dfrac{9}{7} + x = \dfrac{5}{2}$
$ <=> x = \dfrac{5}{2} - \dfrac{9}{7} = \dfrac{35}{14} - \dfrac{18}{14} = \dfrac{17}{14}$
b,
$ \dfrac{22}{7} : \dfrac{11}{63} - x = \dfrac{3}{2}$
$ <=> \dfrac{22}{7} . \dfrac{63}{11} - x = \dfrac{3}{2}$
$ <=> 18 - x = \dfrac{3}{2}$
$ <=> x = 18 - \dfrac{3}{3} = \dfrac{36}{2} - \dfrac{3}{2} = \dfrac{33}{2}$
c,
$ 3,75 × X + 2,43 × X = 27$
$ <=> X × ( 3,75 + 2,43) = 27$
$ <=> X × 6,18 = 27$
$ <=> X = 27 : 6,18 = 27 : \dfrac{309}{50}$
$ <=> X = 27 . \dfrac{50}{309} = \dfrac{450}{103}$
Giải thích các bước giải:
