From polynomial to function

Dear all.
I would like to use legendre polynomials which is something pretty easy in R.

x<-legendre.polynomials(2)[[3]]

x

-0.5 + 1.5*x^2

str(x)

Class 'polynomial'  num [1:3] -0.5 0 1.5

As you can see from the code above str(x) returns that x is of class polynomial. I want to use that polynomial as a function. The reason for that is that I would be grateful if I can feed that kind of function inside integrate(f,lower=,upper=)

Could you please inform if it is possible to do that in R?

I would like to thank you in advance for your help

Best Regards
Alex