因式分解 84x²-91x+21= 12x²+11x-15= 2x³+16x²+30x= 7x²y²-19xy-6= 8x³y-16x²y²-42xy³= 2(x-y)²+5(y-x)-12= (x²+2x)²-4(x²+2x)-32=?

1)
84x²-91x+21
=7(4x-3)(3x-1)

2)
12x²+11x-15
=(4x-3)(3x+5)

3)
2x³+16x²+30x
=2x(x²+8x+15)
=2x(x+3)(x+5)

4)
7x²y²-19xy-6
=(xy-3)(7xy+2)

5)
8x³y-16x²y²-42xy³
=2xy(4x²-8xy-21y²)
=2xy(2x-7y)(2x+3y)

6)
2(x-y)²+5(y-x)-12
=2(x-y)²-5(x-y)-12
=[(x-y)-4][2(x-y)+3]
=(x-y-4)(2x-2y+3)

7)
(x²+2x)²-4(x²+2x)-32
=[(x²+2x)-8][(x²+2x)+4]
=(x-2)(x+4)(x²+2x+4)

因式分解
1 84x^2－91x+21
=7(12x^2－13x+3)
=7(4x－3)(3x－1)

2 12x^2+11x－15
=(4x－3)(3x+5)

3 2x^3+16x^2+30x
=2x(x^2+8x+15)
=2x(x+3)(x+5)

4 7x^y^2－19xy－6
=(7xy+2)(xy－3)

5 8x^3y－16x^2y^2－42xy^3
=2xy(4x^2－8xy+21y^2)
=2xy(2x+3y)(2x－7y)

6 2(x－y)^2+5(y－x)－12
=2(x－y)^2－5(x－y)－12
=[2(x－y)+3]*[(x－y)－4]
=(2x－2y+3)(x－y－4)

7 (x^2+2x)^2－4(x^2+2x)－32
=(x^2+2x－8)(x^2+2x+4)
=(x－2)(x+4)(x^2+2x+4)

因式分解
1 84x^2－91x+21
=7(12x^2－13x+3)
=7(4x－3)(3x－1)

2 12x^2+11x－15
=(4x－3)(3x+5)

3 2x^3+16x^2+30x
=2x(x^2+8x+15)
=2x(x+3)(x+5)

4 7x^y^2－19xy－6
=(7xy+2)(xy－3)

5 8x^3y－16x^2y^2－42xy^3
=2xy(4x^2－8xy+21y^2)
=2xy(2x+3y)(2x－7y)

6 2(x－y)^2+5(y－x)－12
=2(x－y)^2－5(x－y)－12
=[2(x－y)+3]*[(x－y)－4]
=(2x－2y+3)(x－y－4)

7 (x^2+2x)^2－4(x^2+2x)－32
=(x^2+2x－8)(x^2+2x+4)
=(x－2)(x+4)(x^2+2x+4)