## $Im(f\otimes 1_M)=Im(f)\otimes M$ for flat module M

Suppose $$N,N’$$ are both $$A$$ modules and $$f:N\rightarrow N’$$ is an $$A$$ module homomorphism and $$M$$ is a flat $$A$$ module. How does one show that $$Im(f\otimes 1_{M})=Im(f)\otimes M$$, where $$f\otimes 1_{M}:N\otimes M\rightarrow N’\otimes M$$?