y=- 1/ 2 x2-x+ 3 /2
=- 1/ 2( x^2+2x+1)+1/ 2+3/2
=- 1/ 2( x+1)^2+2
向右平移3个单位,左加右减
=- 1/ 2( x+1- 3)^2+2
=- 1/ 2( x- 2)^2+2
=-1/2x²+2x
y=- 1/ 2 x2-x+ 3 /2
=- 1/ 2( x^2+2x+1)+1/ 2+3/2
=- 1/ 2( x+1)^2+2
向右平移3个单位,左加右减
=- 1/ 2( x+1- 3)^2+2
=- 1/ 2( x- 2)^2+2
=-1/2x²+2x