-22t+(6r=15rs) : Not Equivalent (Uses "=" instead of "+")
6r-(22t+15(rs)) : Not Equivalent (Rearranges terms)
(15r+6r)s-22t : Not Equivalent (Rearranges terms)
15(rs+(-22t+6r) : Equivalent (Rearranges terms)
(15s)r+(6t-22r) : Equivalent (Rearranges terms)