giải các phương trình sau a)\(\left\{{}\begin{matrix}3\left(x-1\right)-\sqrt{1-2y}=1\\\left(x-1\right)+2\sqrt{1-2y}=5\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}\sqrt{x^2-2x+1}-3y=7\\2\left|x-1\right|-8y=1\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}2\left(x^2-x\right)+\sqrt{y-4}=0\\3\left(x^2-x\right)-2\sqrt{y-4}=-7\end{matrix}\right.\)
Hai số a,b thỏa mãn \(\left\{{}\begin{matrix}a,b>0\\\left(\sqrt{a}+1\right)\left(\sqrt{b}+1\right)\ge4\end{matrix}\right.\)
Chứng minh \(\dfrac{a^2}{b}+\dfrac{b^2}{a}\ge2\)
Cho \(\left\{{}\begin{matrix}a,b\ge0\\a^2+b^2-\sqrt{ab}=1\end{matrix}\right.\). Tìm giá trị lớn nhất và giá trị nhỏ nhất của biểu thức: \(P=a^2+ab+b^2\)
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
giải hệ phương trình (theo 4 cách):
a/ \(\left\{{}\begin{matrix}\sqrt{5}x-y=\sqrt{5}\left(\sqrt{3}-1\right)\\2\sqrt{3}x+3\sqrt{5}y=21\end{matrix}\right.\)
b/ \(\left\{{}\begin{matrix}1,7x-2y=3,8\\2,1x+5y=0,4\end{matrix}\right.\)
Ghpt:
a) \(\left\{{}\begin{matrix}\left(4x^2+1\right).x+\left(y-3\right)\sqrt{5-2y}=0\\4x^2+y^2+2\sqrt{3-4x}=7\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}x^2+y^2=5\\\sqrt{y-1}\left(x+y-1\right)=\left(y-2\right)\sqrt{x+y}\end{matrix}\right.\)
cho \(\left\{{}\begin{matrix}a,b,c>0\\abc\ge1\end{matrix}\right.\)
chứng minh: \(\sqrt{a^2+1}+\sqrt{b^2+1}+\sqrt{c^2+1}\) ≤\(\sqrt{2}\)(a+b+c)
1,Ghpt:\(\left\{{}\begin{matrix}x^2+3y+1=\left(x+3\right)\sqrt{y^2+1}\\\sqrt{2x\left(x+y\right)^3}+y\sqrt{2\left(x^2+y^2\right)}=3\left(x^2+y^2\right)\end{matrix}\right.\)
2,Cho a,b,c,d∈Z tm:\(a^2+b^2+c^2=d^2\)
CMR:\(abc⋮4\) (xét chẵn lẻ)
a) \(\left\{{}\begin{matrix}x^2-y^2=3\left(x-y\right)\\xy=2\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}x\sqrt{y}+y\sqrt{x}=6\\x^2y+y^2x=20\end{matrix}\right.\)