Sửa đề: \(\dfrac{a^2-3c^2}{b^2-3d^2}=\dfrac{ac}{bd}\)
Đặt a/b=c/d=k
=>a=bk; c=dk
\(\dfrac{a^2-3c^2}{b^2-3d^2}=\dfrac{b^2k^2-3\cdot d^2k^2}{b^2-3d^2}=k^2\)
\(\dfrac{ac}{bd}=\dfrac{bk\cdot dk}{bd}=k^2\)
Do đó: \(\dfrac{a^2-3c^2}{b^2-3d^2}=\dfrac{ac}{bd}\)
cho a/b =c/d.CMR :
a^2-3c^3/b^2-3d^2 = ac/bd
1)Cho a/a+b=c/c+d
Chứng minh rằng: a/b= c/d
2)cho a/b=c/d, chứng minh rằng
a)3a+2c/3b+2d=-5a+3c/-5b+3d
b)a^2/b^2=2c^2-ac/2d^2-b-d
NHANH NHA! MÌNH ĐANG CẦN GẤP!!!
1. cho \(\dfrac{a}{b}\) = \(\dfrac{d}{c}\)
a) \(\dfrac{a+b}{b}\) = \(\dfrac{c+d}{d}\)
b) \(\dfrac{a}{a-b}\) = \(\dfrac{c}{c-d}\)
c) \(\dfrac{2a-5b}{2c-5d}\) = \(\dfrac{3a+4b}{3c+4d}\)
d) \(\dfrac{a^2-c^2}{b^2-d^2}\) = \(\dfrac{ac}{bd}\)
HELP ME !!! MK SẼ TICK CHO
Cho TLT a/b=c/d. Chứng minh 3a+4b/5a-3b = 3c+4d/5c-3d bằng 2 cách
Bài 1. Cho \(\dfrac{a}{b}=\dfrac{c}{d}\)
Chứng minh a/3a+b= c/3c+d
Bài 2. Cho a/b= c/d. Chứng minh: a. a^2 - b^2/c^2-d^2 = ab/cd
b. (a-b)^2/(c-d)^2 = ab/cd
Bài 3. Tìm x,y biết 2/x=3/y và xy= 96
1. Cho \(\dfrac{a}{b}\) = \(\dfrac{c}{d}\) c/m
a) (2a+3c) . (2b-3d) = (2a- 3c) . (2b+3d)
b) \(\dfrac{\left(a^2+c\right)^2}{\left(b+d\right)^2}\) = \(\dfrac{\left(a-c\right)^2}{\left(b-d\right)^2}\)
c)\(\dfrac{a^3+b^3}{c^3+d^3}\) = \(\dfrac{a^3-b^3}{c^3-d^3}\)
d) \(\dfrac{a^{2018}-b^{2018}}{a^{2018}+b^{2018}}\) = \(\dfrac{c^{2018}-d^{2018}}{c^{2018}+d^{2018}}\)
HELP ME >~< !!!
Tìm a , b , c biết :
a, a = \(\dfrac{b}{2}\) = \(\dfrac{c}{3}\) và a - b + c = 10
b, 2a = 3b ; 5b = 7c và 3a - 7b +5c = 30
c, \(\dfrac{a-1}{2}\) = \(\dfrac{b-2}{3}\) = \(\dfrac{c-3}{4}\) và a - 2b + 3c = 14
d, a : b : c = 3 : 4 : 5 và 2a2 + 2b2 - 3c2 = -100
Tìm a,b,c biết a/6=b/-3=c/2 và 2a+b+3c=39
Cho a/b = c/d
a, C/m : \(\frac{a^2+ac}{c^2-ac}=\frac{b^2+bd}{b^2-bd}\)
b, C/m : \(\frac{10a^2+5ab}{16a^2-b^2}=\frac{10c^2+5cd}{16c^2-d^2}\)
