The minimum value of quadratic function x2 + 4x + 1
x²+4x+1
=x²+4x+4-4+1
=(x+2)²-3
So x = - 2, the minimum is - 3
When the quadratic function y = x2-4x + 6 takes the minimum value, the value of the independent variable x is
y=x²-4x+6=﹙x-2﹚²+2≥2
When x = 2, the minimum value of quadratic function y = x2-4x + 6 is 2