因式分解3x2+4xy-y2实数范围内因式分解

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因式分解3x2+4xy-y2实数范围内因式分解

因式分解3x2+4xy-y2实数范围内因式分解
因式分解3x2+4xy-y2
实数范围内因式分解

因式分解3x2+4xy-y2实数范围内因式分解
3x2+4xy-y2
=3x²-(y²-4xy)
=3x²-(y²-4xy+4x²)+4x²
=7x²-(y-2x)²
=(√7x+y-2x)(√7x-y+2x)
=[(√7-2)x+y][(√7+2)x-y]

原式=3(x²+4xy/3-y²/3)
=3(x²+4xy/3+4y²/9-4y²/9-y²/3)
=3[(x-2y/3)²-7y²/9]
=3(x-2y/3+√7y/3)(x-2y/3-√7y/3)