#"The vertex form is formed as y="a(x-h)^2+k#
#"Where (h,k) is vertex coordinates"#
#"we should rearrange the given equation."#
#y=1/2x^2+3/2x-4#
#y=1/2x^2+3/2xcolor(red)(+9/8-9/8)-4#
#y=1/2(color(green)(x^2+3x+9/4))-9/8-4#
#color(green)(x^2+3x+9/4)=(x+3/2)^2#
#y=1/2(x+3/2)^2-41/8#