[tex]P_{c} =P_{b} +2\cdot P_{p} \\\\P_{p} =x\cdot (x+1)=x^{2} +x\\\\P_{b}=2\cdot [x\cdot (x+3) ]+2\cdot [(x+1)\cdot (x+3)]=2\cdot (x^{2} +3x)+2\cdot (x^{2} +3x+x+3)=2x^{2} +6x+2x^{2} +8x+6=4x^{2} +14x+6\\\\P_{c} =4x^{2} +14x+6+2x^{2} +2x=6x^{2} +16x+6\\\\\\Odp:~~A.6x^{2} +16x+6[/tex]
