text: f(x)=3x and g(x)=4x-3, find f[g(5)] and g[f(5)].?   given that f(x)=3x            g(x)=4x+3 to find f[g(5)]: g(5)=4(5)-3                      =20-3                      =17            now f[g(5)]=f(17)                      =3(17)                      =51   to find g[f(5)]:f(5)=3(5)                     =15           now g[f(5)]=g(15)                      =4(15)-3                      =60-3                      =57   so,f[g(5)]=51    and    g[f(5)]=57