\(B=\frac{\left(1,09-0,29\right).1\frac{1}{4}}{\left(18,9-16\frac{13}{20}\right).\frac{8}{9}}=\frac{0,8.\frac{5}{4}}{\left[\left(18+0,9\right)-\left(16+\frac{13}{20}\right)\right].\frac{8}{9}}\)

\(B=\frac{\frac{4}{5}.\frac{5}{4}}{\left(18+\frac{9}{10}-16-\frac{13}{20}\right).\frac{8}{9}}\)

\(B=\frac{1}{\left[\left(18-16\right)+\left(\frac{9}{10}-\frac{13}{20}\right)\right].\frac{8}{9}}\)

\(B=\frac{1}{\left(2+\frac{1}{4}\right).\frac{8}{9}}\)

\(B=\frac{1}{\frac{9}{4}.\frac{8}{9}}=\frac{1}{2}\)

Bằng \(\frac{1}{2}\)

\(\frac{\left(1,09-0,29\right)x\frac{5}{4}}{\left(18,9-16,65\right)x\frac{8}{9}}\)=\(\frac{\frac{4}{5}x\frac{5}{4}}{\frac{9}{4}x\frac{8}{9}}\)=\(\frac{1}{2}\)\(=0,5\)

\(A=\frac{0,87.7+0,8^2}{\left(1,25.7-\frac{4}{5}.1,25\right)+31,64}\)

\(A=\frac{0,87\left(7+0,8\right)}{\left[1,25\left(7-\frac{4}{5}\right)\right]+31,64}\)

\(A=\frac{6,786}{7,75+31,64}\)

\(A=\frac{87}{505}\)

\(B=\frac{\left(1,09-0,29\right).\frac{5}{4}}{\left(18,9-16,65\right).\frac{8}{9}}\)

\(B=\frac{0,8.\frac{5}{4}}{2,25.\frac{8}{9}}\)

\(B=\frac{1}{2}\)

        A gấp B số lần là:\(\frac{87}{505}:\frac{1}{2}=\frac{174}{505}\)

A gấp 160 lần B

a= 80

b= 0,5

\(\Rightarrow\)a gấp 160 lần b

a=80

b=0,5

=> a gấp 160 lần b

Ta có
\(M=\left[0,8\times7+\left(0,8\right)^2\right]\times\left(1,25\times7-\frac{4}{5}\times125\right)+31,64\):\(M=\left[\frac{28}{5}+\frac{16}{25}\right]\times\left(\frac{35}{4}-1\right)+31,64\)\(=\frac{156}{25}\times\frac{31}{4}+31,64\)\(=48,36+31,64=80\)

và \(B=\frac{\left(1,09-0,29\right)\times\frac{5}{4}}{\left(18,9-16,65\right)\times\frac{8}{9}}=\frac{\frac{4}{5}\times\frac{5}{4}}{\frac{9}{4}\times\frac{8}{9}}=\frac{1}{2}=0,5\)
M gấp: \(80:0,5=160\)lần B
k đúng nha

 

M gấp B số lần là : -1075,52