初一代数式求值几个经典题目（高悬赏!）谁能给我几个啊?要题带答案,高悬赏!要求值的题,越多越好哦!快

1、(3ab-2a)÷a =a(3b-2)/a=3b-2 2、（x^3-2x^y)÷(-x^2)= x-2y 3、-21a^2b^3÷7a^2b =-3b^2 4、(6a^3b-9a^c)÷3a^2 =3a^2(2ab-3c)/3a^2=2ab-3c 5、(5ax^2+15x)÷5x=5x(a+3x)÷5x =a+3x 6、(a+2b)(a-2b)=a^2-4b^2 7...