1.因式分解:x^4+64=____
2.在实数范围内因式分解:
(1)x^2-5x+3
(2)x^2-2根号2x-3
(3)3x^2+4xy-y^2
求解题过程,多多帮忙~.~
1.因式分解:x^4+64=____
2.在实数范围内因式分解:
(1)x^2-5x+3
(2)x^2-2根号2x-3
(3)3x^2+4xy-y^2
求解题过程,多多帮忙~.~
1、x^4+64=X^4+64+16X^2-16X^2
=(X^2+8)-16X^2
=(X^2+8-4X)(X^2+8+4X)
2、①、x^2-5x+3=0两根为(5±√13)/2,因此,为(x-5/2+√13/2)(x-5/2-√13/2)
② 、x^2-2√2x-3=x^2-2√2x+2-5=(x-√2)^2-5=(x-√2+√5)(x-√2-√5)
③、3x^2+4xy-y^2
=3(x^2+xy*4/3-y^2*1/3)
=3[(x^2+2*2/3*xy+4/9y^2)-y^2/3-4/9y^2]
=3[(x+2/3y)^2-7/9y^2]
=3(x+2/3y+√7/3y)(x+2/3y-√7/3y)
=3[x+(2+√7)/3y][x+(2-√7)/3y]
1、x^4+64=(x^4+16x^2+64)-16x^2=(x^2+8)^2-16x^2=(x^2+4x+8)(x^2-4x+8)
x^4+64
=X^4+64+16X^2-16X^2 =(X^2+8)-16X^2 =(X^2+8-4X)(X^2+8+4X)
这是第一个