Solve for r\displaystyle {r} within the complex number system. 

(2r2+12r+16)(3r28r+4)(7r228)=0\displaystyle {\left({2}{r}^{{2}}+{12}{r}+{16}\right)}{\left({3}{r}^{{2}}-{8}{r}+{4}\right)}-{\left({7}{r}^{{2}}-{28}\right)}={0}

r=\displaystyle {r}=