甲、乙两名同学进行的因式分解:甲:x²-xy+4x-4y=(x²-xy)+(4x-4y)(分成两组)=x(x-y)+4(x-y)(直接提公因式)=(x-5y)(x+4)乙:a²-b²-c²+2bc=a²-(b²+c²-2bc)(分成两
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![甲、乙两名同学进行的因式分解:甲:x²-xy+4x-4y=(x²-xy)+(4x-4y)(分成两组)=x(x-y)+4(x-y)(直接提公因式)=(x-5y)(x+4)乙:a²-b²-c²+2bc=a²-(b²+c²-2bc)(分成两](/uploads/image/z/956889-9-9.jpg?t=%E7%94%B2%E3%80%81%E4%B9%99%E4%B8%A4%E5%90%8D%E5%90%8C%E5%AD%A6%E8%BF%9B%E8%A1%8C%E7%9A%84%E5%9B%A0%E5%BC%8F%E5%88%86%E8%A7%A3%EF%BC%9A%E7%94%B2%EF%BC%9Ax%26sup2%3B%EF%BC%8Dxy%2B4x%EF%BC%8D4y%3D%28x%26sup2%3B%EF%BC%8Dxy%29%2B%284x%EF%BC%8D4y%29%28%E5%88%86%E6%88%90%E4%B8%A4%E7%BB%84%EF%BC%89%3Dx%28x%EF%BC%8Dy%29%2B4%28x%EF%BC%8Dy%29%28%E7%9B%B4%E6%8E%A5%E6%8F%90%E5%85%AC%E5%9B%A0%E5%BC%8F%EF%BC%89%3D%EF%BC%88x%EF%BC%8D5y%29%28x%2B4%29%E4%B9%99%EF%BC%9Aa%26sup2%3B%EF%BC%8Db%26sup2%3B%EF%BC%8Dc%26sup2%3B%2B2bc%3Da%26sup2%3B%EF%BC%8D%28b%26sup2%3B%2Bc%26sup2%3B%EF%BC%8D2bc%29%28%E5%88%86%E6%88%90%E4%B8%A4)
甲、乙两名同学进行的因式分解:甲:x²-xy+4x-4y=(x²-xy)+(4x-4y)(分成两组)=x(x-y)+4(x-y)(直接提公因式)=(x-5y)(x+4)乙:a²-b²-c²+2bc=a²-(b²+c²-2bc)(分成两
甲、乙两名同学进行的因式分解:
甲:x²-xy+4x-4y=(x²-xy)+(4x-4y)(分成两组)=x(x-y)+4(x-y)(直接提公因式)=(x-5y)(x+4)
乙:a²-b²-c²+2bc=a²-(b²+c²-2bc)(分成两组)=a²-(b-c)²(直接提公因式)=(a+b-c)(a-b+c)
请你在他们的解法的启发下,完成下面的因式分解:
(1)m³-2m²-4m+8;(2)x²-2xy+y²-9
甲、乙两名同学进行的因式分解:甲:x²-xy+4x-4y=(x²-xy)+(4x-4y)(分成两组)=x(x-y)+4(x-y)(直接提公因式)=(x-5y)(x+4)乙:a²-b²-c²+2bc=a²-(b²+c²-2bc)(分成两
(1)m³-2m²-4m+8
=(m³-2m²)-(4m-8)
=m²(m-2)-4(m-2)
=(m-2)(m+2)(m-2)
=(m+2)(m-2)²
(2)x²-2xy+y²-9
=(x-y)²-9
=(x-y+3)(x-y-3)
(1)m³-2m²-4m+8;
=m²(m-2)-4(m-2)
=(m-2)(m+2)(m-2)
=(m+2)(m-2)²
(2)x²-2xy+y²-9
=(x-y)²-9
=(x-y+3)(x-y-3)
1)原式=(m^3-2m^2)+〔-(4m+8)〕
=m^(m+2)+〔-4(m+2)〕
=(m^2-4)(m+2)
=(m+2)(m-2)(m+2)
=(m-2)(m+2)^2
2)原式=-〔3^2-(x²-2xy+y²)〕
=-〔3^2-(x-y)^2〕
=-(3+x-y)(3-x+y)
=(x-y+3)(x-y-3)
(1)m³-2m²-4m+8;
=m²(m-2)-4(m-2)
=(m²-4)(m-2)
=(m-2)(m+2)(m-2)
=(m+2)(m-2)²
(2)x²-2xy+y²-9
=(x-y)²-9
=(x-y+3)(x-y-3)