m的三次方-2m的二次方-15m
=m³-2m²-15m
=m(m²-2m-15)
=m(m+3)(m-5)
m的四次方-17m的二次方+16
=m^4-17m²+16
=(m²-1)(m²-16)
=(m+1)(m-1)(m+4)(m-4)
x的二次方y的二次方-15xy+50
=x²y²-15xy+50
(xy-5)(xy-10)
(x+y)的二次方-14(x+y)+24
=(x+y)²-14(x+y)+24
=(x+y-2)(x+y-12)
(m的二次方-4m)的二次方-(m的二次方-4m)-20
=(m²-4m)²-(m²-4m)-20
=(m²-4m+4)(m²-4m-5)
=(m-2)²(m+1)(m-5)