Question 1129793
Find the vertex of the graph of f(x)= 3x^2-12x+5 and determine whether the graph opens up or down 


is there a formula to figure this out. please help and thank you
<pre>Standard form of a quadratic function: {{{matrix(1,3, f(x), "=", ax^2 + bx + c)}}}
In this case, a = 3; b = - 12; c = 5
The formula for the x-coordinate or axis of symmetry is: {{{matrix(1,3, x, "=", - b/(2a))}}}
{{{matrix(1,7, x, "=", - - 12/(2 * 3), "=", 12/6, "=", 2)}}} ----- Substituting - 12 for b, and 3 for a
{{{matrix(1,13, f(x), or, y, "=", 3(2)^2 - 12(2) + 5, "======>", f(x), or, y, "=", 12 - 24 + 5, "=", - 7)}}} ------- Substituting 2 for x
{{{highlight_green(matrix(1,3, "Vertex:", "(2,", "- 7)"))}}}
Since a = 3, a > 0, or is POSITIVE so the graph opens UPWARD.
IGNORE that woman's answer as she posted a WRONG vertex!!