gt => 12a2 - 4b2 = 3a2 + 3b2
<=> 9a2 = 7b2
\(\Rightarrow\dfrac{a^2}{b^2}=\left(\dfrac{a}{b}\right)^2=\dfrac{7}{9}\Rightarrow\dfrac{a}{b}=\pm\sqrt{\dfrac{7}{9}}\)
Cho: \(^{\dfrac{a}{b}=\dfrac{c}{d}\left(a,b,c,d\ne0\right)}\)
Chứng minh:
a) \(\dfrac{2a+7b}{3a-4b}=\dfrac{2c+7d}{3c-4d}\)
b) \(\dfrac{4a^2-5ab}{3a^2+7b^2}=\dfrac{4c^2-5cd}{3c^2+7d^2}\)
giúp mình gấp nha! Thanks
Tìm x biết
a) \(\dfrac{-2}{5}+\dfrac{5}{3}\left(\dfrac{3}{2}-\dfrac{4}{15}x\right)=\dfrac{-7}{6}\)
b) \(\left(\dfrac{1}{4}x-1\right)+\left(\dfrac{2}{3}x-2\right)-\left(\dfrac{5}{8}x+1\right)=5\)
Ai nhanh 3 tick nha
cho \(\dfrac{3a^{2^{ }}-b^{2^{ }}}{a^{2^{ }}+b^2}=\dfrac{3}{4}\)
tính \(\dfrac{a}{b}\)
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) . Chứng minh :
a, \(\dfrac{a^3+b^3}{c^3+d^3} = \dfrac{a^3-b^3}{c^3-d^3}\)
b, \(\dfrac{(a+b)^3}{(c+d)^3}=\dfrac{a^3+b^3}{c^3+d^3}\)
c, \(\dfrac{(a-b)^3}{(c-d)^3}=\dfrac{3a^2+2b^2}{3c^2+2d^2}\)
d, \(\dfrac{4a^4+5b^4}{4c^4+5d^4}=\dfrac{a^2b^2}{c^2d^2}\)
e, \(\dfrac{a^{10}+b^{10}}{(a+b)^{10}} = \dfrac{c^{10}+d^{10}}{(c+d)^{10}}\)
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\) . Chứng minh:
a) \(\dfrac{a}{c}=\dfrac{a+b}{c+d}\)
b) \(\dfrac{b}{d}=\dfrac{a-b}{c-d}\)
c) \(\dfrac{2a+3b}{2c+3d}\)= \(\dfrac{4a-5b}{4c-5d}\)
d) \(\dfrac{a+b}{a}=\dfrac{c+d}{c}\)
e) \(\dfrac{a^2+c^2}{b^2+d^2}=\dfrac{ac}{bd}\)
g) \(\dfrac{a^2+c^2}{b^2+d^2}=\dfrac{a^2-c^2}{b^2-d^2}\)
Các bn giúp mk nhanh nha. Tối nay mk phải nộp cho thầy r. Mk sẽ tick cho.
\(3a-b=\dfrac{1}{2}\left(a+b\right)\) tính \(\dfrac{a^{2022}+3^{2022}}{b^{2022}+5^{2022}}\)
Cho đơn thức :
A=3.(\(a^2+\dfrac{1}{a^2}\)). x2.y4
a, Chứng minh rằng : A luôn > 0 với mọi x
b,Tìm x,y,z để A=0
Ai làm nhanh nhất thì mk tick nha!! Cảm ơn!!
Thực hiện các phép tính sau
a) \(2^3+3.\left(\dfrac{2}{3}\right)^0-2^{-2}+\left[\left(-2\right)^2:\dfrac{1}{2}\right]-8\)
b) \(\left(\dfrac{1}{3}\right)^{-1}-\left(-\dfrac{6}{7}\right)^0+\left(\dfrac{1}{2}\right)^2:2\)
Nhanh nha mai mình đi học
Tìm x, biết:
a) \(\left|x-3\right|-2x=1\)
b) \(\dfrac{4^{x+2}+4^{x+1}+4^x}{21}=\dfrac{3^{2x}+3^{2x+1}+3^{2x+3}}{31}\)
Các bn giúp mk nhanh nha. Tối nay mk phải nộp cho thầy r. Mk sẽ tick cho.
