Question 838075
{{{f(x)=a(x+1)(x-2)(x-4)}}}}
That satisfies the three zeros.
Now use the value to solve for {{{a}}}.
{{{f(1)=a(1+1)(1-2)(1-4)=3}}}
{{{a(2)(-1)(-3)=3}}}
{{{6a=3}}}
{{{a=1/2}}}
{{{highlight_green(f(x)=(1/2)(x+1)(x-2)(x-4))}}}