The tension in a string is $15\mathrm{.}9$ N$,$ and its linear density is $0\mathrm{.}757$ kg$/$m$.$ A wave on the string travels toward the $-$x direction; it has an amplitude of $2\mathrm{.}73$ cm and a frequency of $9\mathrm{.}27$ Hz$.$ What are the speed and wavelength $($in terms of m$)$ of the wave? Write down a mathematical expression for the wave, substituting numbers for the variables A$,$ f$,$ and