#(4u)/(u^2-16)+(2)/(u+7)-(1)/(u+4)#
#=(4u)/((u+4)(u-4))+(2)/(u+7)-(1)/(u+4)#
#=(4u)/((u+4)(u-4))-(1)/(u+4)+(2)/(u+7)#
#=(4u)/((u+4)(u-4))-(u-4)/((u+4)(u-4))+(2)/(u+7)#
#=(4u-(u-4))/((u+4)(u-4))+2/(u+7)#
#=(3u+4)/((u+4)(u-4))+2/(u+7)#
#=((3u+4)(u+7))/((u+4)(u-4)(u+7))+(2(u-4)(u+4))/((u+7)(u-4)(u+4))#
#=((3u+4)(u+7)+2(u+4)(u-4))/((u+4)(u-4)(u+7))#
#=(3u^2+28+25u+2u^2-32)/((u+4)(u-4)(u+7))#
#=(5u^2+25u-4)/((u+4)(u-4)(u+7))#