What is the sum? startfraction 3 over x squared minus 9 endfraction + startfraction 5 over x + 3 endfraction startfraction 8 over x squared + x minus 6 endfraction startfraction 5 x minus 12 over x minus 3 endfraction startfraction negative 5 x over (x + 3) (x minus 3) endfraction startfraction 5 x minus 12 over (x + 3) (x minus 3).