Question 59085
(2)  Given {{{f(x)=3x^2-5x}}}, 
:
(a) Find f(-4)
{{{f(-4)=3(-4)^2-5(-4)}}}
{{{f(-4)=3(16)+20}}}
{{{f(-4)=48+20}}}
{{{highlight(f(-4)=68)}}}
:
(b) Find x if f(x) = 0
{{{0=3x^2-5x}}}
{{{0=x(3x-5)}}}
{{{x=0}}} and {{{3x-5=0}}}
{{{x=0}}} and {{{3x-5+5=0+5}}}
{{{x=0}}} and {{{3x=5}}}
{{{x=0}}} and {{{3x/3=5/3}}}
{{{highlight(x=0)}}} and {{{highlight(x=5/3)}}}
:
(3) Let {{{g(x)=-3(x+72)^2+108}}}
:
(a) Find the zeros of g(x).
{{{0=-3(x+72)^2+108}}}
{{{-108=-3(x+72)^2+108-108}}}
{{{-108=-3(x+72)^2}}}
{{{-108/-3=(x+72)^2}}}
{{{36=(x+72)^2}}}
+\-{{{sqrt(36)=sqrt((x+72)^2)}}}
+\-{{{6=x+72}}}
-72+\-6=x+72-72
{{{x=-72-6}}} and {{{x=-72+6}}}
{{{highlight(x=-78)}}} and {{{highlight(x=-66)}}}
:
(b) Identify the axis of symmetry for the graph of g.
g(x) is in vertex form:{{{highlight(g(x)=a(x-h)^2+k)}}}, the axis of symmetry is x=h.  In your case h=-72, so the axis of symmetry is:
{{{highlight(x=-72)}}}
:
Happy Calculating!!!