=-a8+a8+a8
=a8;
(2)(-3x2y)2 (-2xy3z)3
=9x4y2 (-8x3y9z3)
=-72x7y11z3;
(3)(5a2b-3ab-1)(-3a2)
=-15a4b+9a3b+3a2;
(4)6x2-(x-1)(x+2)-2(x-1)(x+3)
=6x2-(x2+x-2)-2(x2+2x-3)
=6x2-x2-x+2-2x2-4x+6
=3x2-5x+8;
(5)5m×125m÷252m-1
=5m×53m÷54m-2
=25;
(6)[x+2y)(x-2y)+4(x-y)2]÷6x
=[x+2y)(x-2y)+4(x-y)2]÷6x
=[x2-4y2+4x2-8xy+4y2]÷6x
=[5x2-8xy]÷6x
=
5 |
6 |
4 |
3 |