1.x^2-3x-10
问题描述：
1.x^2-3x-10
2.x(x+y)(x-y)-x(x+y)^2
3.9(2a+3b)^2-4(3a-2b)^2
4.已知a^2+a+1=0,求a^3+2a^2+2a+3的值
答
1.(x-5)(x+2)2.x(x+y)[(x-y)-(x+y)]=-2xy(x+y)3.[3(2a+3b)+2(3a-2b)][3(2a+3b)-2(3a-2b)]=13b(12a+5b)4.a^3+2a^2+2a+3=(a^3+a^2+a)+(a^2+a+1)+2 =a(a^2+a+1)+(a^2+a+1)+2=2