1.cho: a,b,c thuoc R thoa man:
a2+b2+c2=a3+b3+c3=1.
Tinh:P=a2013+b2014+c2015
2.tim x thuoc Z sao cho x2+28 la so chinh phuong
3.Cho a,b,c la do dai 3 canh cua mot tam giac.CM:
4ab+c−a+9ba+c−b+16ca+b−c⩾
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???