计算：1.(-6y+x)(-6y-x) 2.(-6y+x)(6y-x) 3.(x+4y)(x-9y) 4.(-6y-x)(6y-x)
问题描述：
计算：1.(-6y+x)(-6y-x) 2.(-6y+x)(6y-x) 3.(x+4y)(x-9y) 4.(-6y-x)(6y-x)
答
1.(-6y+x)(-6y-x) =[-(6y-x)][-(6y+x)] =(6y-x)(6y+x) =(6y)²-x² =36y²-x² 2.(-6y+x)(6y-x) =[-(6y-x)](6y-x) =-(6y-x)(6y-x) =-[(6y-x)²] =-（36y²-12xy-x²） =x²+12xy-36...