问题
解答题
简便计算: (1)(
(2)(x+y+z)(x+y-z).(用乘法公式) |
答案
(1)原式=(
×1 10
×1 9
×…×1 8
×1×10×9×8×…×2×1)101 2
=1;
(2)(x+y+z)(x+y-z)
=(x+y)2-z2
=x2+2xy+y2-z2.
简便计算: (1)(
(2)(x+y+z)(x+y-z).(用乘法公式) |
(1)原式=(
×1 10
×1 9
×…×1 8
×1×10×9×8×…×2×1)101 2
=1;
(2)(x+y+z)(x+y-z)
=(x+y)2-z2
=x2+2xy+y2-z2.