Question

用配方法解y=3x^2-2x+1 和y=1/2x^2-x-3

Answer 1

y=3x^2 -2x+1

=3[x^2 -(2/3)x]+1

=3[x^2 -(2/3)x+(1/9)-(1/9)]+1

=3[x-(1/3)]^2 +(2/3)

y=(1/2)x^2 -x-3

=(1/2)[x^2 -2x-6]

=(1/2)[x^2 -2x+1-7]

=(1/2)(x-1)^2 -(7/2)