YES

3 decompositions
 #1 -----------
   1: F(x1,x2) -> c(x2)

 #2 -----------
   2: G(x3) -> x3

 #3 -----------
   3: f(x4) -> g(x4)
   4: g(x5) -> c(x5)

@Knuth and Bendix' criterion
--- R
   1: F(x1,x2) -> c(x2)

--- S
   1: F(x1,x2) -> c(x2)


@Knuth and Bendix' criterion
--- R
   2: G(x3) -> x3

--- S
   2: G(x3) -> x3


@Knuth and Bendix' criterion
--- R
   3: f(x4) -> g(x4)
   4: g(x5) -> c(x5)

--- S
   3: f(x4) -> g(x4)
   4: g(x5) -> c(x5)