1. Cho x;y;z>0 \[ \frac{1}{1+x} +\frac{1}{1+y}+\frac{1}{1+z}\geq 2 \] .tim GTNN xyz
2. Cho a;b>0 va a+b=2 tim GTLN \[ a^4+b^4 \]
3. Cho \[ 0\leq x \leq 1 \] Tim GTNN \[ y=\frac{2}{1-x}+\frac{1}{x} \]
4. Tim GTLN;GTNN \[ A=x^2+y^2 \] voi x;y thoa man \[ x^2+y^2-xy=4 \]
5. Cho \[ x^4+4x^2=25\]. Tim GTNN;GTLN p=x+2y
6. Tim GTNN
\[ a=x^2+2y^2-2xy+2x-10y\]
\[b=x^2+6y^2+14z^2-8yz+6xz-4xy\]
7. Cho x+t+z=3.tim GTNN \[xy+yz+zx\]
8. Cho \[x;y>0;x+y\leq1 \].tim GTNN \[ a=\frac{1}{x^2+y^2}+\frac{2}{xy}+4xy\]
9. Tim GTLN \[p=\frac{yz\sqrt{x-1}+xz\sqrt{y-1}+yz\sqrt{z-1}}{xyz}\]
10. Cho \[x^2+y^2+z^2\leq27\].tim GTLN;GTNN \[p=x+y+z+xy+yz+zx\]
11. Cho \[x;y>0;x+y\leq1\].tim GTNN \[A=\frac{1}{x^2+y^2}+\frac{2}{xy}\]
12. Cho x;y>0 x+y=1.tim GTNN\[ A=(x+\frac{1}{x})^2+(y+\frac{1}{y})^2\]
13. Cho x;y thoa man \[x^2+3y^2+2xy-10x-14y+18=0\]tim GTLN;GTNN S=x+y
14cho xy+yz+zx=1 tim GTNN\[x^4+y^4+z^4\]
Ai giup em nhanh nhanh ty nha
2. Cho a;b>0 va a+b=2 tim GTLN \[ a^4+b^4 \]
3. Cho \[ 0\leq x \leq 1 \] Tim GTNN \[ y=\frac{2}{1-x}+\frac{1}{x} \]
4. Tim GTLN;GTNN \[ A=x^2+y^2 \] voi x;y thoa man \[ x^2+y^2-xy=4 \]
5. Cho \[ x^4+4x^2=25\]. Tim GTNN;GTLN p=x+2y
6. Tim GTNN
\[ a=x^2+2y^2-2xy+2x-10y\]
\[b=x^2+6y^2+14z^2-8yz+6xz-4xy\]
7. Cho x+t+z=3.tim GTNN \[xy+yz+zx\]
8. Cho \[x;y>0;x+y\leq1 \].tim GTNN \[ a=\frac{1}{x^2+y^2}+\frac{2}{xy}+4xy\]
9. Tim GTLN \[p=\frac{yz\sqrt{x-1}+xz\sqrt{y-1}+yz\sqrt{z-1}}{xyz}\]
10. Cho \[x^2+y^2+z^2\leq27\].tim GTLN;GTNN \[p=x+y+z+xy+yz+zx\]
11. Cho \[x;y>0;x+y\leq1\].tim GTNN \[A=\frac{1}{x^2+y^2}+\frac{2}{xy}\]
12. Cho x;y>0 x+y=1.tim GTNN\[ A=(x+\frac{1}{x})^2+(y+\frac{1}{y})^2\]
13. Cho x;y thoa man \[x^2+3y^2+2xy-10x-14y+18=0\]tim GTLN;GTNN S=x+y
14cho xy+yz+zx=1 tim GTNN\[x^4+y^4+z^4\]
Ai giup em nhanh nhanh ty nha