\(\dfrac{a}{b}=\dfrac{c}{d}=\dfrac{a+c}{b+d}=\dfrac{a-c}{b-d}\)
\(\dfrac{e}{f}=\dfrac{g}{h}=\dfrac{i}{k}=\dfrac{e-g+i}{f-h+k}=\dfrac{e+g+i}{f+h+k}...\)(Giả sử các tỉ số đều có nghĩa)
TRẦN MINH HOÀNG
\(\dfrac{a}{x}=\dfrac{b}{y}=\dfrac{c}{z}=\dfrac{a\pm b\pm c}{x\pm y\pm z}\)
\(\dfrac{a}{b}=\dfrac{c}{d}=\dfrac{a+c}{b+d}=\dfrac{a-c}{b-d}\)
Hoặc
\(\dfrac{a}{b}=\dfrac{c}{d}=\dfrac{e}{h}=\dfrac{a+c+e}{b+d+h}=\dfrac{a-c-e}{b-d-h}=\dfrac{a+c-e}{b+d-h}=\dfrac{a-c+e}{b-d+h}\)