1.cho: a,b,c thuoc R thoa man:
$a^{2}+b^{2}+c^{2}=a^{3}+b^{3}+c^{3}=1.$
$Tinh:P=a^{2013}+b^{2014}+c^{2015}$
2.tim x thuoc Z sao cho $x^2+28$ la so chinh phuong
3.Cho a,b,c la do dai 3 canh cua mot tam giac.CM:
$\frac{4a}{b+c-a}+\frac{9b}{a+c-b}+\frac{16c}{a+b-c}\geqslant 26$
4.Giai phuong trinh:
$\sqrt{4x^{2}+5x+1}-2\sqrt{x^{2}-x+1}=9x-3$
5.Cho$\Delta ABC$,duong cao AH=6;BH=3;$\widehat{CAH}=3\widehat{BAH}$
Tinh:$S\Delta ABC$???