(1)3a²-5ab+2b²=(a-b)(3a-2b)
(2)设原式=(x的三次-3x²+3x-1)(x+m)
=x的四次+mx的三次-3x的三次-3mx²+3x²+3mx-x-m
=x的四次+(m-3)x的三次+(3-3m)x²+(3m-1)x-m
∴m-3=-1 m=2
∴a=3-3m=-3 b=3m-1=5 c=-m=-2
(3)原式=(a²-b²-c²)²-4b²c²
=(a²-b²-c²+2bc)(a²-b²-c²-2bc)
=[a²-(b²+c²-2bc)][a²-(b²+c²+2bc)]
=[a²-(b-c)²][a²-(b+c)²]
=(a+b-c)(a-b+c)(a+b+c)(a-b-c)
∵abc是三角形的三条边
∴两边之和大于第三边
∴原式小于0
(4)(x+y+z)的三次=0
∴6xyz+3x²y+3x²z+3y²x+3y²z+3z²x+3z²y=0
2xyz+x²(y+z)+y²(x+z)+z²(x+y)=0
2xyz-(x的三次+y的三次+z的三次)=0
∴2xyz=0
xyz=0
满意答案哦!