Violympic toán 7
Các câu hỏi tương tự
Cho a/b =c/d .Chứng minh
a. a-b/a+b = c-d/c+d
b.2a + 5b/3a + 4b = 2c - 5d/3c + 4d
Cho \(\dfrac{a}{b}=\dfrac{c}{d}.Cm:\)\(\dfrac{2a+5b}{3a-4b}=\dfrac{2c+5d}{3c-4d}\)
Cho tỉ lệ thức \(\dfrac{a}{b}=\dfrac{c}{d}\) CMR:
\(\dfrac{2a+5b}{3a-4b}=\dfrac{2c+5d}{3c-4d}\)
Tìm các số a,b,c biết:
a)a:b:c:d = 15:7:3:1 và a-b+c-d
b) 2a = 3b ; 5b =7c và 3a +5c-7b=30
c)3a=4b & b-a=5
Cho a+b+c+d khác 0 sao cho: \(\dfrac{b+c+d}{a}=\dfrac{a+c+d}{b}=\dfrac{b+a+d}{c}=\dfrac{c+b+a}{d}\)
Hãy tính: M = \(\dfrac{2a+5b}{3c+4d}-\dfrac{2b+5c}{3d+4a}-\dfrac{2c+5d}{3a+4b}+\dfrac{2d+5a}{3c+4b}\)
cho\(\frac{a}{b}=\frac{c}{d}\) chứng minh rằng:
a, \(\frac{2a+3b}{3a-4b}=\frac{2c+3d}{3c-4d}\)
b, \(\frac{2a^2-3ab+4b^2}{2b^2+5ab}=\frac{2c^2-3cd+4d^2}{2d^2+5cd}\)
NT
18 tháng 6 2019 lúc 16:07
Chứng minh : dfrac{a}{b}dfrac{c}{d} nếu biết :
a,dfrac{4a-3b}{4c-3d}dfrac{4a+3b}{4c+3d}
b,dfrac{2a-3b}{2a+3b}dfrac{2c-3d}{2c+3d}
c,dfrac{3a+5b}{3a-5b}dfrac{3c+5d}{3c-5d}
d,dfrac{4a-3b}{a}dfrac{4c-3d}{c}
e,dfrac{3a-7b}{b}dfrac{3c-7d}{d}
Đọc tiếp
Chứng minh : \(\dfrac{a}{b}=\dfrac{c}{d}\) nếu biết :
a,\(\dfrac{4a-3b}{4c-3d}=\dfrac{4a+3b}{4c+3d}\)
b,\(\dfrac{2a-3b}{2a+3b}=\dfrac{2c-3d}{2c+3d}\)
c,\(\dfrac{3a+5b}{3a-5b}=\dfrac{3c+5d}{3c-5d}\)
d,\(\dfrac{4a-3b}{a}=\dfrac{4c-3d}{c}\)
e,\(\dfrac{3a-7b}{b}=\dfrac{3c-7d}{d}\)
NT
18 tháng 6 2019 lúc 16:19
Chứng minh dfrac{a}{b}dfrac{c}{d} nếu biết :
a,dfrac{4a-3b}{4c-3d}dfrac{4a+3b}{4c+3d}
b,dfrac{2a-3b}{2a+3b}dfrac{2c-3d}{2c+3d}
c,dfrac{3a+5b}{3a-5b}dfrac{3c+5d}{3c-5d}
d,dfrac{4a-3b}{a}dfrac{4c-3d}{c}
e,dfrac{3a-7b}{b}dfrac{3c-7d}{d}
Đọc tiếp
Chứng minh \(\dfrac{a}{b}=\dfrac{c}{d}\) nếu biết :
a,\(\dfrac{4a-3b}{4c-3d}=\dfrac{4a+3b}{4c+3d}\)
b,\(\dfrac{2a-3b}{2a+3b}=\dfrac{2c-3d}{2c+3d}\)
c,\(\dfrac{3a+5b}{3a-5b}=\dfrac{3c+5d}{3c-5d}\)
d,\(\dfrac{4a-3b}{a}=\dfrac{4c-3d}{c}\)
e,\(\dfrac{3a-7b}{b}=\dfrac{3c-7d}{d}\)
a) Cho dfrac{a}{b}dfrac{c}{d} (a,b,c,dne0). Chứng minh rằng:
1) dfrac{2a+5b}{3a-4b}dfrac{2c+5d}{3c-4d}
2) dfrac{ab}{cd}dfrac{a^2+b^2}{c^2+d^2}
3) dfrac{a^3+b^3}{c^3+d^3}dfrac{left(a+bright)^3}{left(c+dright)^3} left(dfrac{a}{b}dfrac{c}{d}ne1right)
b)Cho dfrac{2a+13b}{3a-7b}dfrac{2c+13d}{3c-7d}. Chứng minh rằng:dfrac{a}{b}dfrac{c}{d}
c)Cho dfrac{cy-bz}{x}dfrac{az-cx}{y}dfrac{bx-ay}{z}. Chứng minh rằng: dfrac{a}{x}dfrac{b}{y}dfrac{c}{z}
Đọc tiếp
a) Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) (\(a,b,c,d\ne0\)). Chứng minh rằng:
1) \(\dfrac{2a+5b}{3a-4b}=\dfrac{2c+5d}{3c-4d}\)
2) \(\dfrac{ab}{cd}=\dfrac{a^2+b^2}{c^2+d^2}\)
3) \(\dfrac{a^3+b^3}{c^3+d^3}=\dfrac{\left(a+b\right)^3}{\left(c+d\right)^3}\) \(\left(\dfrac{a}{b}=\dfrac{c}{d}\ne1\right)\)
b)Cho \(\dfrac{2a+13b}{3a-7b}=\dfrac{2c+13d}{3c-7d}\). Chứng minh rằng:\(\dfrac{a}{b}=\dfrac{c}{d}\)
c)Cho \(\dfrac{cy-bz}{x}=\dfrac{az-cx}{y}=\dfrac{bx-ay}{z}\). Chứng minh rằng: \(\dfrac{a}{x}=\dfrac{b}{y}=\dfrac{c}{z}\)