Find the local linearization of f(x) near 0 and use this to approximate the value of a. $$ f(x) = (1+x)^\frac35, a= (1.2)^\frac35 $$

I got the linear approximation equation of $$1+ \frac35 x$$
What do I do with the value of a?
Since $$ f(x) = (1+x)^\frac35 \approx 1+\frac35x$$, then $f(a)=f(1.2)=f(1+0.2)\approx1+\frac35\times 0.2=1.12$
Hint: $f(x)=a$ when $x=\cdots\,$.

Find $f(x)$ approximately by using this $x$ value in the linear approximation.