Question 996306
Start with the factored form and fill in the roots.

{{{f(x)=a(x-(1+sqrt(2)))(x-(1-sqrt(2)))}}}


Simplify INCOMPLETELY but keep a as a separate factor.
{{{f(x)=a((x-1)-sqrt(2))((x-1)+sqrt(2))}}}
{{{highlight_green(f(x)=a((x-1)^2-2))}}}
This is almost in standard form, but next.....



Next, use the given point to solve for a.
{{{a=f(x)/((x-1)^2-2)}}}
POINT (1,6)
{{{a=6/((1-1)^2-2)}}}
{{{highlight_green(a=-3)}}}


You know how to finish?