請幫忙解解決兩條數學難題!

2007-11-10 9:28 pm
請幫忙解解決兩條數學難題!
1.(x的二次-2x)+(3-4x+x的二次)
2.(5-4y的二次)-(5y-y的二次+3)
備注:要有過程

回答 (3)

2007-11-10 10:07 pm
✔ 最佳答案
1) (x^2-2x)+(3-4x+x^2)
先拆括號!
x^2-2x+3-4x+x^2
2x^2-6x+3
二次公式!
x= -(-6)加滅√(-6)^2-4(2)(3)/2(2)
x=6加滅√12/4


2) (5-4y^2)-(5y-y^2+3)
先拆括號!
5-4y^2-5y+y^2-3
-3y^2-5y+2
二次公式
y= -(-5)加滅√(-5)^2-4(-3)(2)/2(-3)
y=5加減√49/-6
y=5加減7/-6
y= -2或x=1/3
2007-11-10 10:07 pm
1.
(x^2-2x)+(3-4x+x^2)
=x^2-2x+3-4x+x^2
=x^2+x^2-2x-4x+3
=2x^2-6x+3

2.
(5-4y^2)-(5y-y^2+3)
=5-4y^2-5y+y^2-3
=-4y^2+y^2-5y+5-3
=-3y^2-5y+2
2007-11-10 9:38 pm
1.(x的二次-2x)+(3-4x+x的二次)
 =x的二次-2x+3-4x+x的二次
 =2x的二次-6x+3

2. (5-4y的二次)-(5y-y的二次+3) 
  =5-4y的二次-5y+y的二次-3
  =-3y的二次-5y+2

2007-11-10 13:39:59 補充:
又快又準最佳解答..please!
參考: me


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