Áp dụng tính chất dãy tỉ số bằng nhau
\(\frac{x}{5}=\frac{y}{7}=\frac{z}{9}=\frac{x-y+z}{5-7+9}=\frac{315}{7}=45\)
suy ra: x/5 = 45 => x = 225
y/7 = 45 => y = 315
z/9 = 45 => z = 405
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\left(b,d\ne0\right)\).Chứng minh rằng
\(\dfrac{2a+b}{2a-b}=\dfrac{2c+d}{2c-d}\)
\(\dfrac{2a+b}{a-2b}=\dfrac{2c+d}{c-2d}\)
chứng minh a/b = c/d
2a+2b/2a-2b = 2c+2d/2c-2d
Cho : 2a+b/a-2b=2c+d/c-2d
Chứng minh a/b=c/d
Cho 2a + b + c + d/a = a + 2b + c + d/b = a + b+ 2c + d/c = a + b + c + 2d. Chứng minh rằng a = b = c
Cho \(\frac{a+2c}{b+2d}=\frac{2a+c}{2b+d}\) .
CMR : \(\frac{a}{b}=\frac{a+c}{b+d};\frac{2a-c}{2b-d}=\frac{a-2c}{b-2d};\frac{a+2b}{a-b}=\frac{c+2d}{c-d}\)
cho a/b=c/d chứng minh 2a-3b/a+2b=2c-3d/c+2d
cho a/b=c/d chứng minh 2a-3b/a+2b=2c-3d/c+2d
Cho:\(\frac{a}{b}=\frac{b}{c}=\frac{c}{d}=\frac{d}{a}\)
Tính: P\(\frac{2a-b}{2c-d}+\frac{2b-c}{2d-a}+\frac{2c-d}{2a-b}+\frac{2d-a}{2b-c}\)
Giúp với ai nhanh mình tick cho.
Cho a/2b=b/2c=c/2d=d/2a(a,b,c,d>0)
