từ a/b = c/d => a/c = b/d => 5a/5c = 3b/3d
áp dụng tính chất của dãy tỉ số bằng nhau ta có:
\(\frac{5a}{5c}=\frac{3b}{3d}=\frac{5a+3b}{5c+3d}=\frac{5a-3b}{5c-3d}\)
từ: \(\frac{5a+3b}{5c+3d}=\frac{5a-3b}{5c-3d}\)áp dụng tính chất ta dc
\(\frac{5a+3b}{5a-3b}=\frac{5c+3d}{5c-3d}\)(đcpm)
CMR nếu a/b=c/d thì 5a+3b/5a-3b = 5c+3d/5c-3d ( bằng 3 cách )
\(cho\frac{a}{b}=\frac{c}{d}CMR\frac{5a+3b}{5a-3b}=\frac{5c+3d}{5c-3d}\)
cho a/b=c/d chứng minh 5a+3b/5a-3b=5c+3d/5c-3d
cho a/b=c/d chứng minh 5a+3b/5a-3b=5c+3d/5c-3d
a) Cho \(\dfrac{a}{b}\)=\(\dfrac{c}{d}\) CMR: \(\dfrac{5a+3b}{5a-3b}\)=\(\dfrac{5c+3d}{5c-3d}\)
b) CMR: Nếu \(\dfrac{a}{b}\)=\(\dfrac{c}{d}\) thì : \(\dfrac{a}{b}\)=\(\dfrac{3a+2c}{3b+2d}\)
c) CMR: Nếu \(\dfrac{a}{b}\)=\(\dfrac{c}{d}\) thì \(\dfrac{7a^2+3ab}{11a^2-8b^2}\) = \(\dfrac{7c^2+3cd}{11c^{2^{ }}-8d^2}\)
cho a/b =c/d ( a,b,c,dkhác 0)
CMR :
a) a-b/a+b=c-d/c+d
b) 5a+3b/5a-3b=5c+3d/5c-3d
cho\(\dfrac{a}{b}\)=\(\dfrac{c}{d}\)chứng minh rằng\(\dfrac{5a+3b}{5a-3b}=\dfrac{5c+3d}{5c-3d}\)
CMR nếu a/b=c/d thì : \(\frac{5a+3b}{5a-3b}=\frac{5c+3d}{5c-3d}\)
CHO TỈ LỆ THỨC a/b=c/d . chứng minh 5a+3b/5a-3b=5c+3d/5c-3d
