x方-2x+3其中x=2/根3-1

x方-2x+3其中x=2/根3-1
x方-2x+3其中x=2/根3-1

x方-2x+3其中x=2/根3-1
x=2/(√3-1)
=2(√3+1)/(√3-1)(√3+1)
=2(√3+1)/(3-1)
=√3+1
x²-2x+3
=x²-2x+1+2
=(x-1)²+2
=(√3+1-1)²+2
=(√3)²+2
=3+2
=5

因为x=2/根3-1=根号3+1
所以x-1=根号3
所以(x-1)²=3
所以x²-2x+1=3
所以x²-2x+3=5

求这个式子的值？x=2/(√3-1)=√3+1
x^2-2x+3=x(x-2)+3=(√3+1)(√3-1）+3=5