问题
解答题
计算: (1)x2y-
(2)(3a-2)-3(a+5) (3)(4a2b-5ab2)-(3a2b-4ab2) (4)3x2-[7x-3(4x-3)-2x2]. |
答案
(1)原式=(1-
-2)x2y2 5
=-
x2y;7 5
(2)原式=3a-2-3a-15
=-17;
(3)原式=4a2b-5ab2-3a2b+4ab2
=a2b-ab2;
(4)原式=3x2-[7x-12x+9-2x2]
=3x2-7x+12x-9+2x2
=5x2+5x-9.