Question

a)tìm phân số a/b,biết:5-(a/b+1/2)=2 và 1/3

b)tính giá trị biểu thức: (3/4+ 2 và 1/2):3/5-3

giúp mình nha hứa sẽ tist mà nha 

mấy bạn giải ra giúp mình lun nha

CẢM ƠN RẤT NHIỀU

Answer 1

a, \(5-\left(\frac{a}{b}+\frac{1}{2}\right)=2\frac{1}{3}\)   =>  \(\frac{a}{b}+\frac{1}{2}=5-2\frac{1}{3}\) =>  \(\frac{a}{b}+\frac{1}{2}=\frac{8}{3}\)  => \(\frac{a}{b}=\frac{8}{3}-\frac{1}{2}\) =>  \(\frac{a}{b}=\frac{13}{6}\)

b, \((\frac{3}{4}+2\frac{1}{2}):\frac{3}{5-3}=\left(\frac{3}{4}+\frac{5}{4}\right):\frac{3}{5}-1=\frac{9}{4}:\frac{-2}{5}=\frac{-45}{8}\)

Answer 2

a, 5-(\(\frac{a}{b}\)+\(\frac{1}{2}\))=2\(\frac{1}{3}\)

<=>5-\(\frac{a}{b}-\frac{1}{2}\)=\(\frac{7}{3}\)

<=>\(\frac{a}{b}=5-\frac{1}{2}-\frac{7}{3}\)

<=>\(\frac{a}{b}=\frac{13}{6}\)

b,(\(\frac{3}{4}\)+2\(\frac{1}{2}\)):\(\frac{3}{5}\)-3

=(\(\frac{3}{4}\)+\(\frac{5}{2}\)).\(\frac{5}{3}\)-3

=\(\frac{23}{4}\).\(\frac{5}{3}\)-3

=\(\frac{115}{12}\)-3

=\(\frac{115-36}{12}\)

=\(\frac{79}{12}\)

Answer 3

a) \(5-\left(\frac{a}{b}+\frac{1}{2}\right)=2\frac{1}{3}\)

\(\Rightarrow5-\left(\frac{a}{b}+\frac{1}{2}\right)=\frac{7}{3}\)

\(\Rightarrow\frac{a}{b}+\frac{1}{2}=5-\frac{7}{3}\)

\(\Rightarrow\frac{a}{b}+\frac{1}{2}=\frac{8}{3}\)

\(\Rightarrow\frac{a}{b}=\frac{8}{3}-\frac{1}{2}\)

\(\Rightarrow\frac{a}{b}=\frac{13}{6}\)

Vậy \(\frac{a}{b}=\frac{13}{6}\)

b) \(\left(\frac{3}{4}+2\frac{1}{2}\right):\frac{3}{5}-3\)

\(=\left(\frac{3}{4}+\frac{5}{2}\right):\frac{3}{5}-3\)

\(=\frac{13}{4}:\frac{3}{5}-3\)

\(=\frac{65}{12}-3\)

\(=\frac{29}{12}\)

Học tốt #