分解因式①4m^2 -n^2-2m-n ②3x^2y-2x^2+12xy-8x ③2x^2-5x-ax+3a-3④5x^3-2x^2 y+8y-20x

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分解因式①4m^2 -n^2-2m-n ②3x^2y-2x^2+12xy-8x ③2x^2-5x-ax+3a-3④5x^3-2x^2 y+8y-20x

分解因式①4m^2 -n^2-2m-n ②3x^2y-2x^2+12xy-8x ③2x^2-5x-ax+3a-3④5x^3-2x^2 y+8y-20x
分解因式①4m^2 -n^2-2m-n ②3x^2y-2x^2+12xy-8x ③2x^2-5x-ax+3a-3
④5x^3-2x^2 y+8y-20x

分解因式①4m^2 -n^2-2m-n ②3x^2y-2x^2+12xy-8x ③2x^2-5x-ax+3a-3④5x^3-2x^2 y+8y-20x
①4m^2 -n^2-2m-n
=(2m+n)(2m-n)-(2m+n)
=(2m+n)(2m-n-1)
②3x^2y-2x^2+12xy-8x
=x²(3y-2)+4x(3y-2)
=x(3y-2)(x+4)
③2x^2-5x-ax+3a-3
=2x²-5x-3-ax+3a
=(2x+1)(x-3)-a(x-3)
=(x-3)(2x+1-a)
④5x^3-2x^2 y+8y-20x
=x²(5x-2y)-4(5x-2y)
=(5x-2y)(x²-4)
=(5x-2y)(x+2)(x-2)