因式分解：a^2×b^2-4ab-5

题目

因式分解：a^2×b^2-4ab-5
x^4+6x^2+8
(x+y)^2-3(x+y)+2

答案

a^2×b^2-4ab-5
=（ab-5)(ab+1)
x^4+6x^2+8
=(x²+2)(x²+4)
(x+y)^2-3(x+y)+2
=[(x+y)-1][(x+y-2]
=(x+y-1)(x+y-2)