1. CM:
a) Nếu \(\frac{a+b}{a-b}=\frac{c+a}{c-a}\) thì \(a^2=bc\)
b) Nếu \(\frac{a}{b}=\frac{c}{d}\) thì \(\frac{\left(a+b\right)^2}{a^2-b^2}=\frac{\left(c+d\right)^2}{c^2-d^2}\)
c) Nếu \(\frac{a-c}{b-c}=\frac{b+c}{a+c}\)thì a=b
Bài 1 nếu a+b/c-d =c+d/c-d thì a/b = c/d
Bài 2 nếu b^2=a.c thì a/c=(a+2007b)^2/(b+2007c)^2
cho a,b,c khác 0 và a^2=b.c
CMR:a^2+c^2/b^2+d^2=c/b
CMR: nếu a/b=c/d thì a^2+b^2=b^2+d^2=a/d
Cmr nếu a/b=c/d thì
a. a+b/a-b=c+d/c-d
b. (a+b)^2/(a-b)^2=(c+d)^2/(c-d)^2
c. 2a+5b/3a-4b=2c+5d/3c-4d
CMR nếu : a/b = b/c = c/d thì a+b/c+d = b^2 + c^2
CMR nếu a/b=c/d thì (a^2+b^2)/(b^2+d^2)=a/d
C/M:
nếu a/b = b/d thì a^2 + b^2/b^2 + d^2 = a/d
cm: nếu \(\frac{a}{b}=\frac{c}{d}\)thì \(\frac{a^2+b^2}{c^2+d^2}=\frac{ab}{cd}\)
Cho a/b=c/d cm rằng a)a/a-b=c/c-d
b) a/b=a+c/b+d
c) a/3a+b=c/3c+d
d)a.b/bd=a^2+c^2/b^2+d^2
E) a.b/c.d=a^2-b^2/c^2-d^2
F) a.b/c.d=(a-b)^2/(c-d)^2