Question 947821
(Second attempt):


{{{y=a(x-r)(x-s)}}}, factored generally but not a square.


Notice the two roots are given as their points.

Roots 0 and 3.


{{{y=a(x-0)(x-3)}}}
{{{y=a*x(x-3)}}}
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The last given point will allow finding the value for a.
{{{a=y/(x(x-3))}}}
{{{a=4/(-1(-1-3))}}}
{{{a=4/((-1)(-4))}}}
{{{a=1}}}
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EQUATION:   {{{highlight(y=x(x-3))}}}