在实数范围内分解因式:(1)x²+x-1 (2)x²-2x-6 (3)2x²+8x-7 (4)x²-5xy+3y²(5)-2x²-3x+6(6)4x²y²+xy-1
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![在实数范围内分解因式:(1)x²+x-1 (2)x²-2x-6 (3)2x²+8x-7 (4)x²-5xy+3y²(5)-2x²-3x+6(6)4x²y²+xy-1](/uploads/image/z/8597151-63-1.jpg?t=%E5%9C%A8%E5%AE%9E%E6%95%B0%E8%8C%83%E5%9B%B4%E5%86%85%E5%88%86%E8%A7%A3%E5%9B%A0%E5%BC%8F%EF%BC%9A%281%29x%26%23178%3B%2Bx-1+%282%29x%26%23178%3B-2x-6+%283%292x%26%23178%3B%2B8x-7+%284%29x%26%23178%3B-5xy%2B3y%26%23178%3B%285%29-2x%26%23178%3B-3x%2B6%286%294x%26%23178%3By%26%23178%3B%2Bxy-1)
在实数范围内分解因式:(1)x²+x-1 (2)x²-2x-6 (3)2x²+8x-7 (4)x²-5xy+3y²(5)-2x²-3x+6(6)4x²y²+xy-1
在实数范围内分解因式:(1)x²+x-1 (2)x²-2x-6 (3)2x²+8x-7 (4)x²-5xy+3y²
(5)-2x²-3x+6
(6)4x²y²+xy-1
在实数范围内分解因式:(1)x²+x-1 (2)x²-2x-6 (3)2x²+8x-7 (4)x²-5xy+3y²(5)-2x²-3x+6(6)4x²y²+xy-1
(1)x²+x-1=x²+x+1/4-5/4=(x+1/2)²-5/4=(x+1/2+√5/2)(x+1/2-√5/2)
(2)x²-2x-6=x²-2x+1-7=(x-1)²-7=(x-1+√7)(x-1-√7)
(3)2x²+8x-7=2(x²+4x-7/2)=2(x²+4x+4-15/2)=2[(x+2)²-15/2]=2[(x+2)²-15/2]=2(x+2+√30/2)(x+2-√30/2)
(4)x²-5xy+3y²=x²-5xy+25/4y²-13/4y²=(x-5/2y)²-13/4y²=(x-5/2y+√13/2y)(x-5/2y-√13/2y)
(5)-2x²-3x+6=-2(x²+3/2x-3)=-2(x²+3/2x+9/16-57/16)=-2[(x+3/4)²-57/16]=-2(x+3/4+√57/4)(x+3/4-√57/4)
(6)4x²y²+xy-1=4x²y²+xy+1/16-17/16=(2xy+1/4)²-17/16=(2xy+1/4+√17/4)(2xy+1/4-√17/4)