1) Tính nhanh
a)\(\frac{63^2-47^2}{215^2-105^2}\)
b)\(\frac{2006^3+1}{2006^2-2005}\)
c)\(\frac{2006^3-1}{2006^2+2007}\)
d)10\(^2\)+8\(^2\)+6\(^2\)+......+2\(^2\)-(9\(^2\)+7\(^2\)+......+1\(^2\))
2)Tìm x, pk
a)4(x+1)\(^2\)+(2x-1)\(^2\)-8(x-1)(x+1)=11
b)(x-3)(x\(^2\)+3x+9)+x(x+2)(2-x)=1
c)(x+1)\(^3\)-(x-1)\(^3\)-6(x-1)\(^2\)=-10