Question

[Nguyen Ngoc Lien]

Tìm x trong các tỉ lệ sau :

a) \(\frac{x}{27}=\frac{-2}{3,6}\)

b)  -0,52 : x = -9,36 : 16,38

c) \(\frac{4\frac{1}{4}}{2\frac{7}{8}}=\frac{x}{1,61}\)

giúp mình nha 

Answer 1

[Phương An]

\(\frac{x}{27}=-\frac{2}{3,6}\)

\(x=\frac{-2\times27}{3,6}\)

\(x=-15\)

***

\(\frac{-0,52}{x}=\frac{-9,36}{16,38}\)

\(x=\frac{-0,52\times16,38}{-9,36}\)

\(x=0,91\)

***

\(\frac{4\frac{1}{4}}{2\frac{7}{8}}=\frac{x}{1,61}\)

\(\frac{4,25}{2,875}=\frac{x}{1,61}\)

\(x=\frac{4,25\times1,61}{2,875}\)

\(x=2,38\)

Answer 2

[Trần Nguyễn Bảo Quyên]

\(a.\)

\(\frac{x}{27}=\frac{-2}{3,6}\)

\(\Rightarrow x=\frac{\left(-2\right).27}{3,6}\)

\(\Rightarrow x=\frac{-54}{3,6}\)

\(\Rightarrow x=-15\)

Vậy :        \(x=-15\)

\(b.\)

\(-0,52:x=-9,36:16,38\)

\(\Rightarrow\frac{-0,52}{x}=-\frac{4}{7}\)

\(\Rightarrow x=\frac{-0,52.7}{-4}\)

\(\Rightarrow x=0,91\)

Vậy :         \(x=0,91\)

\(c.\)

\(\frac{4\frac{1}{4}}{2\frac{7}{8}}=\frac{x}{1,61}\)

\(\Rightarrow\frac{\frac{17}{4}}{\frac{23}{8}}=\frac{x}{1,61}\)

\(\Rightarrow\frac{17}{4}.\frac{8}{23}=\frac{x}{1,61}\)

\(\Rightarrow\frac{34}{23}=\frac{x}{1,61}\)

\(\Rightarrow x=\frac{1,61.34}{23}\)

\(\Rightarrow x=\frac{119}{50}\)

Vậy :         \(x=\frac{119}{50}\)