The general vertex form for a quadratic is y = m(x-a)+b where (a,b) is the vertex.
y=2x^2-12x+11 color(white)("XXXX")extract the m y=2(x^2-6x) +11 color(white)("XXXX")complete the square y=2(x^2-6x+9) +11 -18 color(white)("XXXX")simplify to vertex form y=2(x-3)^2 + (-7) color(white)("XXXX")with the vertex at (3,-7)