Consider the conservative force field

$F=(20x^{3}y+3-y)i+x(5x^3-1)j$

Find a function $f(x,y)$ such that $F=$vec$(grad)f.$

$f=$

Use this result to find the work done if this force field moves an object from the point $(2,2)$ along the piecewise linear path to $(6,2),$ and from there to $(9,5).$

Work $=$