Question

20x2+253x+800因式分解 x4+y4+(x+y)4因式分解

Answer 1

20x2+253x+800

=(5X+32)(4X+25)

(x+y)²=(x+y)²（x+y)²=（x²+y²+2xy）²=(x²+y²)²+4x²y²+4xy(x²+y²)

x4+y4=(x²+y²)²-2x²y²

x4+y4+(x+y)4=(x²+y²)²+4x²y²+4xy(x²+y²)+(x²+y²)²-2x²y²=2(x²+y²)²+2x²y²+4xy(x²+y²)

=2[(x²+y²)²+x²y²+2xy(x²+y²)]=2(x²+y²+xy)²