F4 maths (2 questions)

2007-09-16 12:25 am
Solve the following equations.
1) 3(x-2)2 = x(x-2)
2) (x -1)(2x+3) = (x-1)(x-4)

回答 (5)

2007-09-16 12:30 am
✔ 最佳答案
1。 3 (x^2-4x+4)=x^2-2x
3x^2-12x+12=x^2-2x
2x^2-10x+12=0
x^2-5x+6=0
(x-2)(x-3)+0
x= 2 or 3

2. 2x^2+x-3=x^2-5x+4
x^2+6x-7=0
(x+7)(x-1)=0
x= -7 or 1
2007-09-16 1:15 am
1) 3(x-2)2 = x(x-2)
3[(x)^2-2(x)(2)+(2)^2]=x^2-2x
3(x^2-4x+4)=x^2-2x
3x^2-12x+12=x^2-2x
3x^2-x^2-12x+2x+12=0
2x^2-10x+12=0
2x -6(交差相乘)
x -2
=-6x-4x= -10x
(2x-6)(x-2)=0
2x-6=0 or x-2=0
x=3 or x=2
2) (x -1)(2x+3) = (x-1)(x-4)
 2x^2+3x-2x-3=x^2-4x-x+4
2x^2-x^2+3x-2x+4x+x-3-4=0
x^2+6x-7=0
x -1
x +7
=7x-x=6x  
(x-1)(x+7)=0
x-1=0 or x+7=0
x=1 or x= -7
2007-09-16 12:52 am
1) 3(x-2)^2 = x(x-2)
3(x^2-4x+4) = x^2-2x
3x^2-12x+12 = x2^-2x
2x^2-10x+12 = 0
x^2-5x+6 = 0
(x-2)(x-3) = 0
x = 2 or x = 3

2) (x -1)(2x+3) = (x-1)(x-4)
2x^2+x-3 = x^2-5x+4
x^2+6x-7 = 0
(x+7)(x-1) = 0
x = -7 or x = 1
參考: me,,
2007-09-16 12:36 am
1) 3(x-2)^2 = x(x-2)
3(x^2-4x+4)=x^2-2x
3x^2-12x+12=x^2-2x
2x^2-10x+12=0
x^2-5x+6=0
(x-3)(x-2)=0
x=3 or x=2
2) (x-1)(2x+3)=(x-1)(x-4)
2x^2+x-3=x^2-5x+4
x^2+6x-7=0
(x-1)(x+7)=0
x=1 or x=-7
參考: me
2007-09-16 12:31 am
1,
3(x-2)^2 = x(x-2)
3(x^2-4x+4)=x^2-2x
3x^2-12x+12=x^2-2x
3x^2-x^2-12x+2x+12=0
2x^2-10x+12=0
x^2-5x+6=0
(x-3)(x-2)=0
so x-3=0 or x-2=0
x=3 or x=2

2.
(x-1)(2x+3)=(x-1)(x-4)
2x^2+3x-2x-3=x^2-4x-x+4
2x^2-x^2+x+4x+x-3-4=0
x^2+6x-7=0
(x+7)(x-1)=0
x+7=0 or x-1=0
x=-7 or x=1
參考: myself


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