\(\dfrac{4}{x}=\dfrac{12}{15}=\dfrac{y}{45}\)
Ta có:
\(12:4=3\)
\(\Rightarrow\dfrac{4}{x}=\dfrac{4\times3}{x\times3}=\dfrac{12}{15}\)
Mà \(15:3=5\)
\(\Rightarrow x=5\)
Lại có:
\(45:15=3\)
\(\Rightarrow\dfrac{12}{15}=\dfrac{12\times3}{15\times3}=\dfrac{y}{45}\)
Mà \(12\times y=36\)
\(\Rightarrow y=36\)
Vậy \(x=5;y=36\).
\(\dfrac{3}{x}=\dfrac{1}{y}=\dfrac{6}{24}\)
Ta có:
\(\dfrac{3}{x}=\dfrac{6}{24}\)
\(6\times x=3\times24\)
\(6\times x=72\)
\(x=72:6\)
\(x=12\)
\(\Rightarrow x=12\)
Lại có:
\(\dfrac{3}{12}=\dfrac{1}{y}\)
\(3\times y=1\times12\)
\(3\times y=12\)
\(y=12:3\)
\(y=4\)
\(\Rightarrow y=4\)
Vậy \(x=12;y=4\).
phần a hình như sai đề
phần b x=12 ;y=4
tìm x,y hả em
\(\dfrac{4}{x}\text{=}\dfrac{12}{15}\text{=}\dfrac{y}{45}\)
\(\dfrac{4}{x}\text{=}\dfrac{12:3}{15:3}\text{=}\dfrac{4}{5}\)
\(\dfrac{12\times3}{15\times3}\text{=}\dfrac{y}{45}\)
\(\Rightarrow x\text{=}5;y\text{=}36\)
\(\dfrac{3}{x}\text{=}\dfrac{1}{y}\text{=}\dfrac{6}{24}\)
\(\dfrac{3}{x}\text{=}\dfrac{6:2}{24:2}\text{=}\dfrac{3}{12}\)
\(\dfrac{1}{y}\text{=}\dfrac{3}{x}\text{=}\dfrac{3:3}{12:3}\text{=}\dfrac{1}{4}\)
\(\Rightarrow x\text{=}12;y\text{=}4\)
Bạn sửa dòng thứ 10 giúp mình thành:
Mà \(12\times3=36\)
\(\Rightarrow y=36\)
