计算:
(1)a•a2•a3+(-2a3)2-a6
(2)(x+3)(x-1)+x(x-2)
(3)(a+3b-2c)(a-3b-2c)
(1)原式=a6+4a6-a6
=4a6;
(2)原式=x2+2x-3+x2-2x
=2x2-3;
(3)原式=[(a-2c)+3b][(a-2c)-3b]
=(a-2c)2-(3b)2
=a2-4ac+4c2-9b2.
计算:
(1)a•a2•a3+(-2a3)2-a6
(2)(x+3)(x-1)+x(x-2)
(3)(a+3b-2c)(a-3b-2c)
(1)原式=a6+4a6-a6
=4a6;
(2)原式=x2+2x-3+x2-2x
=2x2-3;
(3)原式=[(a-2c)+3b][(a-2c)-3b]
=(a-2c)2-(3b)2
=a2-4ac+4c2-9b2.