Do you mean in vertex form? If so, then complete the square...
y= 3(x^2 + 6x + 9) +7 - 27... the +9 comes from taking half of 6 and squaring it. Since 3*9=27 and you added it, you also need to subtract it.
Then factor y = 3(x+3)(x+3) - 20 followed by y = 3(x+3)^2 - 20.
Vertex is (-3, -20)