\(\dfrac{28x}{45}=\dfrac{77}{165}\)

=>\(x\cdot\dfrac{28}{45}=\dfrac{7}{15}\)

=>\(x=\dfrac{7}{15}:\dfrac{28}{45}=\dfrac{7}{15}\cdot\dfrac{45}{28}=\dfrac{3}{4}\)

a: \(1-\dfrac{4}{15}=\dfrac{15-4}{15}=\dfrac{11}{15}\)

b: \(\dfrac{-5}{16}\cdot\dfrac{4}{15}=\dfrac{-4}{16}\cdot\dfrac{5}{15}=\dfrac{-1}{4}\cdot\dfrac{1}{3}=\dfrac{-1}{12}\)

bằng 6,486242254 nha

cách trình bày đâu bạn ???

1: \(\left(-\dfrac{3}{4}+\dfrac{1}{6}\right):\left(\dfrac{5}{9}-\dfrac{1}{6}\right)\)

\(=\dfrac{-3\cdot3+2}{12}:\dfrac{5\cdot2-3}{18}\)

\(=\dfrac{-7}{12}\cdot\dfrac{18}{7}=\dfrac{-18}{12}=\dfrac{-3}{2}\)

2: \(\dfrac{6}{7}+\dfrac{5}{7}:5-\dfrac{8}{9}\)

\(=\dfrac{6}{7}+\dfrac{1}{7}-\dfrac{8}{9}\)

\(=1-\dfrac{8}{9}=\dfrac{1}{9}\)

3: \(\dfrac{1}{5}-\left(-\dfrac{3}{2}\right)+\dfrac{4}{7}-\dfrac{3}{-10}\)

\(=\dfrac{1}{5}+\dfrac{3}{2}+\dfrac{4}{7}+\dfrac{3}{10}\)

\(=\dfrac{2}{10}+\dfrac{15}{10}+\dfrac{3}{10}+\dfrac{4}{7}=2+\dfrac{4}{7}=\dfrac{18}{7}\)

4: \(\dfrac{3}{22}-\left(\dfrac{7}{15}-\dfrac{-3}{22}\right)+\dfrac{7}{15}-\dfrac{1}{2}\)

\(=\dfrac{3}{22}-\dfrac{7}{15}+\dfrac{3}{22}+\dfrac{7}{15}-\dfrac{1}{2}\)

\(=\dfrac{3}{11}-\dfrac{1}{2}=\dfrac{6-11}{22}=\dfrac{-5}{22}\)

5: \(\left(-\dfrac{5}{24}+\dfrac{3}{4}+\dfrac{7}{12}\right):\left(-2\dfrac{1}{8}\right)\)

\(=\dfrac{-5+18+7\cdot2}{24}:\dfrac{-17}{8}\)

\(=\dfrac{27}{24}\cdot\dfrac{8}{-17}=\dfrac{-9}{17}\)

7/3

\(\dfrac{7}{3}\)

a=(118+2)x 10:2=120+200

a=220

bạn ơi nhân 10 là nhân với số có trong dãy

\(\left(\dfrac{1997}{2024}+\dfrac{2021}{1999}\right)-\left(\dfrac{1997}{2024}+\dfrac{22}{1999}\right)\)

\(=\dfrac{1997}{2024}+\dfrac{2021}{1999}-\dfrac{1997}{2024}-\dfrac{22}{1999}\)

\(=\dfrac{2021}{1999}-\dfrac{22}{1999}=\dfrac{1999}{1999}=1\)

(1997/2024+2021/1999)-(1997/2024+22/1999)

= 2021/1999/22/1999

= 1999/1999 = 1

Số tiền phải trả cho cái thứ nhất là \(180000\left(1-30\%\right)=126000\left(đồng\right)\)

Số tiền phải trả cho cái thứ hai là:

\(126000\left(1-5\%\right)=119700\left(đồng\right)\)

Tổng số tiền phải trả là:

\(126000+119700=245700\simeq246000\left(đồng\right)\)