Cho \(\left\{{}\begin{matrix}a,b,c>0\\a^2+b^2+c^2=1\end{matrix}\right.\)
CMR: \(\dfrac{a}{b^2+c^2}+\dfrac{b}{c^2+a^2}+\dfrac{c}{b^2+a^2}\ge\dfrac{3\sqrt{3}}{2}\)
giải các hpt sau: a)\(\left\{{}\begin{matrix}4\sqrt{5}-y=3\sqrt{2}\\10x+\sqrt{2}y=-1\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}\dfrac{3x}{4}+\dfrac{2y}{5}=2,3\\x-\dfrac{3y}{5}=0,8\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}\left|x-1\right|-\dfrac{3}{\sqrt{y-2}}=-1\\2\left|1-x\right|+\dfrac{1}{\sqrt{y-2}}=5\end{matrix}\right.\)cíu zới
Ghpt:
a) \(\left\{{}\begin{matrix}x^2+2y^2=2x-2xy+1\\3x^2+2xy-y^2=2x-y+5\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}4xy+4x^2+4y^2+\dfrac{3}{\left(x+y\right)^2}=7\\2x+\dfrac{1}{x+y}=3\end{matrix}\right.\)
a.\(\sqrt{28a^4}\)
b. A=\(\left(\dfrac{\sqrt{21}-\sqrt{7}}{\sqrt{3-1}}+\dfrac{\sqrt{10}-\sqrt{5}}{\sqrt{2}-1}\right)\)\(\div\)\(\dfrac{1}{\sqrt{7}-\sqrt{5}}\)
c.\(\left\{{}\begin{matrix}\dfrac{3}{2x}-y=6\\\dfrac{1}{x}+2y=-4\end{matrix}\right.\)
Giải các hệ phương trình:
a)\(\left\{{}\begin{matrix}\dfrac{x}{y}=\dfrac{2}{3}\\x+y-10=0\end{matrix}\right.\)
b)\(\left\{{}\begin{matrix}\left(3x+2\right)\left(2y-3\right)=6xy\\\left(4x+5\right)\left(y-5\right)=4xy\end{matrix}\right.\)
c)\(\left\{{}\begin{matrix}\left(2x-3\right)\left(2y+4\right)=4x\left(y-3\right)+54\\\left(x+1\right)\left(3y-3\right)=3y\left(x+1\right)-12\end{matrix}\right.\)
d)\(\left\{{}\begin{matrix}\dfrac{2y-5x}{3}+5=\dfrac{y+27}{4}-2x\\\dfrac{x+1}{3}+y=\dfrac{6y-5x}{7}\end{matrix}\right.\)
Bài 1: Giải hệ PT \(\left\{{}\begin{matrix}\dfrac{1}{2x-2}-\dfrac{1}{y-1}=2\\\dfrac{3}{2x-2}-\dfrac{2}{y-1}=1\end{matrix}\right.\)
Bài 2 : Cho hệ PT \(\left\{{}\begin{matrix}2x+y=1\\x-my=m\end{matrix}\right.\)( m là tham số )
a) Tìm đk của m để hệ PT có nghiệm duy nhất
b) Tìm m để hệ có nghiệm thỏa mãn x > 0 và y > -1
Bài 3 : Cho hệ PT \(\left\{{}\begin{matrix}mx-y=2\\x+my=5\end{matrix}\right.\)( m là tham số )
Tìm m để hệ PT có nghiệm thỏa mãn x + y= 1 - \(\dfrac{m^2}{m^2+1}\)
Giải các hệ phương trình sau bằng phương pháp thế:
a)\(\left\{{}\begin{matrix}3x-2y=11\\4x-5y=3\end{matrix}\right.\)
b)\(\left\{{}\begin{matrix}\dfrac{x}{2}-\dfrac{y}{3}=1\\5x-8y=3\end{matrix}\right.\)
c)\(\left\{{}\begin{matrix}3x+5y=1\\2x-y=-8\end{matrix}\right.\)
d)\(\left\{{}\begin{matrix}\dfrac{x}{y}=\dfrac{2}{3}\\x+y-10=0\end{matrix}\right.\)
Giải hpt
a)\(\left\{{}\begin{matrix}\dfrac{2x}{x+1}+\dfrac{y}{y+1}=2\\\dfrac{x}{x+1}+\dfrac{3}{y+1}=-1\end{matrix}\right.\)
b)\(\left\{{}\begin{matrix}\dfrac{x}{y}-\dfrac{x}{y+12}=1\\\dfrac{x}{y+12}-\dfrac{x}{y}=2\end{matrix}\right.\)
c)\(\left\{{}\begin{matrix}\dfrac{x+y}{xy}+\dfrac{xy}{x+y}=\dfrac{5}{2}\\\dfrac{x-y}{xy}+\dfrac{xy}{x-y}=\dfrac{10}{3}\end{matrix}\right.\)
d)\(\left\{{}\begin{matrix}\dfrac{2x}{y-1}+\dfrac{3y}{x-1}=1\\\dfrac{2y}{x-1}-\dfrac{5x}{y-1}=2\end{matrix}\right.\)
Giải các hệ phương trình sau:
a) \(\left\{{}\begin{matrix}2\left(x+1\right)-3y=-10\\3x+2y+5=0\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}\dfrac{x+1}{2}-\dfrac{y-2}{3}=1\\4x+3y=1\end{matrix}\right.\)