(x+3)(x-3)-4(x-1)=? 30x平方-85x+60=? 21+14x-7x平方=?
回答 (3)
2017-02-03 2:44 pm
✔ 最佳答案
1 (x+3)(x－3)－4(x－1)=x^2－9－4x+4
=x^2－4x－5
=(x－5)(x+1)
2 30x^2－85x+60
=5(6x^2－17x+12)
=5[(6x^2－8x)+(－9x+12)]
=5[2x(3x－4)－3(3x－4)]
=5(2x－3)(3x－4)
3 21+14x－7x^2
=－7(x^2－2x－3)
=－7(x－3)(x+1)
2017-02-03 2:49 pm
(1) (x+3)(x-3)-4(x-1)
= x²- 9 - 4x +4
= x² - 4x - 5
= (x - 5)(x +1)
(2) 30x² - 85x + 60
= 5(6x² - 17x + 12)
= 5(2x-3)(3x-4)
(3) 21+14x-7x²
= 7(3+2x-x²)
= 7(3-x)(1+x)
= x²- 9 - 4x +4
= x² - 4x - 5
= (x - 5)(x +1)
(2) 30x² - 85x + 60
= 5(6x² - 17x + 12)
= 5(2x-3)(3x-4)
(3) 21+14x-7x²
= 7(3+2x-x²)
= 7(3-x)(1+x)
2017-02-05 10:58 pm
1 (x+3)(x－3)－4(x－1)
=x^2－9－4x+4
=x^2－4x－5
=(x－5)(x+1)
2 30x^2－85x+60
=5(6x^2－17x+12)
=5[(6x^2－8x)+(－9x+12)]
=5[2x(3x－4)－3(3x－4)]
=5(2x－3)(3x－4)
3 21+14x－7x^2
=－7(x^2－2x－3)
=－7(x－3)(x+1)
=x^2－9－4x+4
=x^2－4x－5
=(x－5)(x+1)
2 30x^2－85x+60
=5(6x^2－17x+12)
=5[(6x^2－8x)+(－9x+12)]
=5[2x(3x－4)－3(3x－4)]
=5(2x－3)(3x－4)
3 21+14x－7x^2
=－7(x^2－2x－3)
=－7(x－3)(x+1)
收錄日期: 2021-04-18 15:59:42
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20170203040236AA7c55S