Manipulate[Plot[a*(((x-h))^2)+c, {x, -20, 20},AspectRatio-> Automatic,Epilog-> {Red,Thick ,Dashed,Line[{{h,20},{h,-20}}]},PlotStyle -> {Thickness[.005]},PlotRange-> 20, ImageSize -> 600, PlotLabel->Row[{Style[StringForm["y=`1`(x-`3`)^2+`2`",a,c,h],30],Style[StringForm["    "],30],Style["x =",30,Red],Style[h,30,Red],Style["    ",30],Style["Vertex (",30],Style[h,30],Style[",",30],Style[c,30],Style[")",30]}],LabelStyle-> Large], {{a,1, "Width"},-10, 10, .1}, {{c,0,"Vertical Shift"}, -20, 15, 1}, {{h, 0,"Horizontal Shift"},-20,20,1},LabelStyle-> Large, ControlPlacement-> Left, ControlType-> VerticalSlider]