已知:13x^2-12xy+4y^2-4x+1=0求:(3y)^-4x的值

已知:13x^2-12xy+4y^2-4x+1=0求:(3y)^-4x的值


13x^2-12xy+4y^2-4x+1=0(2y)^2-2*2y*3x+(3x)^2+(2x)^2-2*2x+1=0(13x^2=9x^2+4x^2)(2y-3x)^2+(2x-1)^2=0所以只能(2y-3x)^2=0;(2x-1)^2=0得:2y=3x;2x-1=0x=1/2;y=3/4.代入:(3y)^-4x=(3*3/4)^-4*1/2=9/4^-2=16/…



x^2-2x+1=0 4x^2+13x+3=0一般化
探索規律,並一般化,寫出式子.
x^2-2x+1=0
(x-1)(x-1)=0
x=1
x^2-3x+2=0
(x-1)(x-2)=0
x=1 x=2
3x^2+x-2=0
3(x-2/3)(x+1)=0
x=2/3,x=-1
2x^2+5x+2=0
2(x+1/2)(x+2)=0
x=-1/2,x=-2
4x^2+13x+3=0
4(x+1/4)(x+3)=0
x=-1/4,x=-3
以上.結論一般化,寫出式子…


ax^2+(ab+ac)x+abc=0
→a(x+b)(x+c)=0



9分之4x+0.5=9分之13x-1.3


9分之4x+0.5=9分之13x-1.3
9分之13x-9分之4x=1.8
x=1.8



解方程:(1-x^2)^2-4x(1-x-x^2)=0
速度!


(1-x^2)^2-4x(1-x-x^2)
=(1-x^2)^2-4x(1-x^2)+4x^2
=(1-x^2+2x)^2=0
(1-x)^2=0
x=1