(1) m-1/m=3,求m²+1/m²和m^4+1/m^4的值 (2) a-b=3,a²+b=17,求(a+b)²的值

问题描述:

(1) m-1/m=3,求m²+1/m²和m^4+1/m^4的值 (2) a-b=3,a²+b=17,求(a+b)²的值
(3) (2m-3n)=(2m+3n)²+A成立,求A
(4) ①求(x-2)²(x+2)²
②求(x+y)²-(-xy-3)(-xy+3)

(1)m-1/m=3两边平方得m² -2 +1/m²=9m² +1/m²=11两边平方得m^4 +2 +1/m^4=121m^4 +1/m^4=119(2)a-b=3两边平方得a²-2ab+b²=9a²+b²=17∴2ab=17-9=8∴(a+b)²=a²+2ab+...