1.2-(x-5)²的最大值是_________,此时x是__________.2.若a²-a-3=0,求a³-4a²+2的值.3.已知有理数a,b,且a+b

问题描述:

1.2-(x-5)²的最大值是_________,此时x是__________.
2.若a²-a-3=0,求a³-4a²+2的值.
3.已知有理数a,b,且a+b