解1)x²+7x+10=x²+(2+5)x+2×5=(x+2)(x+5).2)x²-10x+24=(x-4)(x-6),3)x²-6x+y²+6y-2xy+5=(x²-2xy+y²)-6(x-y)+5=(x-y)²-6(x-y)+5=(x-y-1)(x-y-5).[以第一题为例,余仿此】.