2.(2x+3)(x-1)
3.(x-1)(x-2)(x-3)
更新1:
要列式
math2
回答 (2)
2007-08-09 6:51 pm
✔ 最佳答案
1.(x+3)(x-2)
= x^2 - 2x + 3x -6
=x^2 + x -6
2.
(2x+3)(x-1)
= 2x^2 - 2x + 3x -3
= 2x^2 + x -3
3.
(x-1)(x-2)(x-3)
= (x^2 - 2x - x + 2)(x-3)
= (x^2 - 3x + 2)(x-3)
= x^3 - 3x^2 - 3x^2 + 9x + 2x - 6
= x^3 - 6x^2 + 11x - 6
: )
參考: me : )
2007-08-09 6:52 pm
1) (x+3)(x+2)
= x (x+3) +2 (x+3)
= x ^2 +3x + 2x +6
= x^2 +5x +5
2) (2x+3)(x-1)
= x (2x+3)- (2x+3)
= 2x^2 +3x -2x-3
= 2 x^2 +x -3
3) (x-1) (x-2) (x-3)
= [x(x-1) - 2 (x-1) ](x-3)
= (x^2 -x-2x+1)(x-3)
= x(x^2-3x+1) -3(x^2-3x+1)
= x^3 -3x^2 +x -3 x^2 +9x-3
= x^3 -6x^2 +10x -3
= x (x+3) +2 (x+3)
= x ^2 +3x + 2x +6
= x^2 +5x +5
2) (2x+3)(x-1)
= x (2x+3)- (2x+3)
= 2x^2 +3x -2x-3
= 2 x^2 +x -3
3) (x-1) (x-2) (x-3)
= [x(x-1) - 2 (x-1) ](x-3)
= (x^2 -x-2x+1)(x-3)
= x(x^2-3x+1) -3(x^2-3x+1)
= x^3 -3x^2 +x -3 x^2 +9x-3
= x^3 -6x^2 +10x -3
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