If the zeros are -7, 5, and -3, then the factors are (x+7), (x-5), (x+3). We have to multiply all those together to get a third degree polynomial. Multiplying out the first 2, we get [tex](x+7)(x-5)=x^2+2x-35[/tex]. Now we'll multiply in that last factor: [tex](x^2+2x-35)(x+3)=x^3+5x^2-29x-105[/tex]. There's your third degree polynomial!!