Chứng minh ab/cd=a^2-b^2/c^2-d^2 biết a/b=c/d
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) CMR :
\(\dfrac{ab}{cd}=\dfrac{a^2-b^2}{c^2-d^2}\)
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Toán lớp 7
Chứng minh ab/cd=a^2-b^2/c^2-d^2 biết a/b=c/d
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) CMR :
\(\dfrac{ab}{cd}=\dfrac{a^2-b^2}{c^2-d^2}\)
