因式分解:12x^2-5x-2;2x^2+4xy+2y^2-8z^2 解方程:{x+y^2=6,y=x};x-12+根号x=0;x^2 +3x+根号(x^2+3x)=6
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![因式分解:12x^2-5x-2;2x^2+4xy+2y^2-8z^2 解方程:{x+y^2=6,y=x};x-12+根号x=0;x^2 +3x+根号(x^2+3x)=6](/uploads/image/z/1108367-71-7.jpg?t=%E5%9B%A0%E5%BC%8F%E5%88%86%E8%A7%A3%EF%BC%9A12x%5E2-5x-2%3B2x%5E2%2B4xy%2B2y%5E2-8z%5E2+%E8%A7%A3%E6%96%B9%E7%A8%8B%EF%BC%9A%7Bx%2By%5E2%3D6%2Cy%3Dx%7D%3Bx-12%2B%E6%A0%B9%E5%8F%B7x%3D0%3Bx%5E2+%2B3x%2B%E6%A0%B9%E5%8F%B7%28x%5E2%2B3x%29%3D6)
因式分解:12x^2-5x-2;2x^2+4xy+2y^2-8z^2 解方程:{x+y^2=6,y=x};x-12+根号x=0;x^2 +3x+根号(x^2+3x)=6
因式分解:12x^2-5x-2;2x^2+4xy+2y^2-8z^2 解方程:{x+y^2=6,y=x};x-12+根号x=0;x^2 +3x+根号(x^2+3x)=6
因式分解:12x^2-5x-2;2x^2+4xy+2y^2-8z^2 解方程:{x+y^2=6,y=x};x-12+根号x=0;x^2 +3x+根号(x^2+3x)=6
12x^2-5x-2=(3x^2-2)*(4x^2+1)
2x^2+4xy+2y^2-8z^2=2(x+y+2z)*(x+y-2z)
解方程:{x+y^2=6,y=x};
y=x
则
x+x^2-6=0
(x+3)*(x-2)=0
x=-3或x=2
x-12+根号x=0;
x=(12-x)^2
x=144+x^2-24x
x^2-25x+144=0
(x-16)*(x-9)=0
x=16或x=9
x^2 +3x+根号(x^2+3x)=6
设x^2+3x=t
则t+根号t=6
根号t=6-t
t=(6-t)^2
(t-4)*(t-9)=0
t=4或t=9
即x^2+3x=4或x^2+3x=9
x^2+3x=4时
(x+4)*(x-1)=0
x=1或x=-4
x^2+3x=9时
(x+3/2)^2=27/4
x=-3/2+3/2*根号3
或x=-3/2-3/2*根号3