Question

Bài 1: Tính giá trị biểu thức a) 3/4 : 5/6 × 3½ b) 5/2 - 1/3 : 1/4 c)5¾ × ( 5 - 3/7) Bài 2: Tìm x a) x + 4/5 = 3/2 b) x - 3/2 = 11/4 c) 4/5 - x = 1/2 d) 4/5 : x = 1

Answer 1

Bài 1:
a) \(\dfrac{3}{4} : \dfrac{5}{6} . 3\dfrac{1}{2}=\dfrac{3}{4} : \dfrac{5}{6} . \dfrac{7}{2}=\dfrac{9}{10} . \dfrac{7}{2}=\dfrac{63}{20}\) 

b) \(\dfrac{5}{2}-\dfrac{1}{3} : \dfrac{1}{4}=\dfrac{5}{2}-\dfrac{4}{3}=\dfrac{15}{6}-\dfrac{8}{6}=\dfrac{7}{6}\) 

c) \(5\dfrac{3}{4} . \left(5-\dfrac{3}{7}\right)=\dfrac{23}{4} . \left(\dfrac{35}{7}-\dfrac{3}{7}\right)=\dfrac{23}{4} . \dfrac{32}{7}=\dfrac{184}{7}\) 
Bài 2:
a) \(x+\dfrac{4}{5}=\dfrac{3}{2}\) 

     \(x\)        \(=\dfrac{3}{2}-\dfrac{4}{5}\) 
  
     \(x\)        \(=\dfrac{7}{10}\) 

b) \(x-\dfrac{3}{2}=\dfrac{11}{4}\) 

    \(x\)         \(=\dfrac{11}{4}+\dfrac{3}{2}\) 

    \(x\)         \(=\dfrac{17}{4}\) 

c) \(\dfrac{4}{5} : x=1\) 

          \(x=\dfrac{4}{5} : 1\) 

          \(x=\dfrac{4}{5} : \dfrac{5}{5}\) 

          \(x=\dfrac{4}{5}\)