Question 882934
The equation would have the form,
{{{f(x)=a(x-6)(x-4)(x-sqrt(2))(x-b)}}}
Since the coefficients are rational, then,
The product of the last two factors must cancel out the x term to eliminate the irrational coefficient. 
That can be done by having a difference of squares since,
{{{(x-c)(x+c)=x^2-c^2}}}
So then,
{{{highlight(b=-sqrt(2))}}}
{{{(x-sqrt(2))(x+sqrt(2))=x^2-2}}}