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Cho tỉ lệ thức: \(\frac{a}{b}=\frac{c}{d}\). Chứng minh: \(\frac{2a^2-3ab+5b^2}{2b^2+3ab}=\frac{2c^2-3cd+5d^2}{2d^2+3cd}\)
1) Cho dfrac{a}{b}dfrac{c}{d} . Chứng minh rằng dfrac{2a^2-3ab+5b^2}{2a^2+3ab}dfrac{2c^2-3cd+5d^2}{2c^2+3cd}
2) Cho dfrac{a}{c}dfrac{c}{b}. Chứng minh rằng dfrac{b^2-c^2}{a^2+c^2}dfrac{b-a}{a}
3) Cho dfrac{a}{b}dfrac{c}{d}.Chứng minh rằngdfrac{3a^6+c^6}{3b^6+d^6}dfrac{left(a+cright)^6}{left(b+dright)^6}
Đọc tiếp
1) Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) . Chứng minh rằng \(\dfrac{2a^2-3ab+5b^2}{2a^2+3ab}=\dfrac{2c^2-3cd+5d^2}{2c^2+3cd}\)
2) Cho \(\dfrac{a}{c}=\dfrac{c}{b}\). Chứng minh rằng \(\dfrac{b^2-c^2}{a^2+c^2}=\dfrac{b-a}{a}\)
3) Cho \(\dfrac{a}{b}=\dfrac{c}{d}\).Chứng minh rằng\(\dfrac{3a^6+c^6}{3b^6+d^6}=\dfrac{\left(a+c\right)^6}{\left(b+d\right)^6}\)
cho \(\dfrac{a}{b}=\dfrac{c}{d}\) . CMR :
a, \(\dfrac{5a+3b}{7a-2b}=\dfrac{5c+3d}{7c-2d}\)
b, \(\dfrac{7a^2+3ab}{11a^2-8b^2}=\dfrac{7c^2+3cd}{11c^2-8d^2}\)
c, \(\left(\dfrac{a+b}{c+d}\right)^2=\dfrac{a^2+b^2}{c^2+d^2}\)
( giả thiết các tỉ số trên đều có nghĩa )
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\). Chứng minh rằng : (2 cách )
a) \(\dfrac{a+5b}{2c+5d}=\dfrac{2a-5b}{2c+5d}\)
b) \(\dfrac{a^2-b^2}{a^2+b^2}\) = \(\dfrac{c^2-d^2}{c^2+d^2}\)
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) . Chứng minh :
\(\dfrac{7a^2+3ab}{11a^2-8b^2}=\dfrac{7c^2+3cd}{11c^2-8d^2}\)
cho\(\frac{a}{b}=\frac{c}{d}\) chứng minh rằng:
a, \(\frac{2a+3b}{3a-4b}=\frac{2c+3d}{3c-4d}\)
b, \(\frac{2a^2-3ab+4b^2}{2b^2+5ab}=\frac{2c^2-3cd+4d^2}{2d^2+5cd}\)
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) chứng minh rằng:
a) \(\dfrac{ab}{cd}=\dfrac{a^2+b^2}{c^2+d^2}\)
b)\(\dfrac{ac}{bd}=\dfrac{a^2+c^2}{b^2+d^2}\)
c)\(\dfrac{7a^2-3ab}{11a^2-8b^2}=\dfrac{7c^2+3cd}{11c^2-8d^2}\)
NN
12 tháng 12 2017 lúc 20:52
Chứng minh rằng nếu \(\dfrac{a}{b}=\dfrac{c}{d}\) thì
a, \(\dfrac{5a+3b}{5a-3b}=\dfrac{5c+3d}{5a-3d}\)
b, \(\dfrac{7a^2+3ab}{11a^2-8b^2}=\dfrac{7c^2+3cd}{11c^2-8d^2}\)
Chứng minh rằng :
\(\dfrac{7a^2+3ab}{11a^2-8b^2}=\dfrac{7c^2+3cd}{11c^2-8d^2}\)