What is the equation of the curve
\[y=f(x)\]
after reflection in the line \[x=k\]
?It is
\[y=f(-(x-2k))\]
.For example
\[y=x^2+2x\]
when reflected in the line \[x=3\]
becomes \[f(-(x-6))=(-(x-6))^3+2(-(x-6))=x^2-12x+36-2x+12=x^2-14x+48\]
.
