x²-4x+1=0;x(x-1)=42,求x值,
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![x²-4x+1=0;x(x-1)=42,求x值,](/uploads/image/z/2729846-38-6.jpg?t=x%26%23178%3B-4x%2B1%EF%BC%9D0%EF%BC%9Bx%EF%BC%88x-1%EF%BC%89%EF%BC%9D42%2C%E6%B1%82x%E5%80%BC%2C)
x²-4x+1=0;x(x-1)=42,求x值,
x²-4x+1=0;x(x-1)=42,求x值,
x²-4x+1=0;x(x-1)=42,求x值,
①x^2-4x+1=0
x^2-4x+4-4+1=0
(x-2)^2-3=0
(x-2+√3)(x-2-√3)=0
x=2-√3或x=2+√3
②x(x-1)/2=21
x(x-1)=42
x²-x-42=0
(x-7)(x+6)=0
x=7或x=-6