3道因式分解,(1)(x^2-5)^2+8(5-x^2)+16(2)a^2-b^2-4a+4(3)2xy-x^2-y^2+1
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3道因式分解,(1)(x^2-5)^2+8(5-x^2)+16(2)a^2-b^2-4a+4(3)2xy-x^2-y^2+1
3道因式分解,
(1)(x^2-5)^2+8(5-x^2)+16
(2)a^2-b^2-4a+4
(3)2xy-x^2-y^2+1
3道因式分解,(1)(x^2-5)^2+8(5-x^2)+16(2)a^2-b^2-4a+4(3)2xy-x^2-y^2+1
1=(X^2-5)^2-8(X^2-5)+16
=(X^2-5-4)^2
=(X^2-9)^2
2=(a^2-4a-4)-b^2
=(a-2)^2-b^2
=(a-2+b)(a-2-b)
3=X^2+Y^2-2XY-1
=-[(x-y)²-1]
=-(x-y-1)(x-y+1)
(1)原式=(x^2-5-4)^2=(x^2-9)^2
(2)原式=(a-2)^2-b^2=(a+b-2)(a-b-2)
(3)原式=-(x-y)^2+1=(1+x-y)(1-x+y)
(1)是完全平方式,直接因式分解(9-X^2)^2
(2)=(a-2)^2-b^2=(a+b-2)(a-b-2)
(3)=-(x^2-2xy+y^2-1)=-((x-y)^2-1)=-(x-y+1)(x-y-1)
1.(x^2-5)^2-8(x^2-5)+16=[x^2-9]^2
2.(a-2)^2-b^2=(a+b-2)(a-b-2)
3.-(x^2-2xy+y^2-1)=-((x-y)^2-1)=-(x-y+1)(x-y-1)
1.=(x²-4x-5)²
=(x-5)²(x+1)²
2.=(a+2)²-b²
=(a-b+2)(a-b-2)
3.=-[(x-y)²-1]
=-(x-y-1)(x-y+1)