3x^n-3x^3+14x^2+13x+2
=3(x^n-x^3+5x^2+x+1)-x^2+10x-1
∴ x^n-x^3+5x^2+x+1与3x^n-3x^3+14x^2+13x+2的公因式一定也是-x^2+10x-1的公因式
而x^2+ax+b是公因式
∴ a=-10,b=1
∴ 1+a+b=1-10+1=-8
3x^n-3x^3+14x^2+13x+2
=3(x^n-x^3+5x^2+x+1)-x^2+10x-1
∴ x^n-x^3+5x^2+x+1与3x^n-3x^3+14x^2+13x+2的公因式一定也是-x^2+10x-1的公因式
而x^2+ax+b是公因式
∴ a=-10,b=1
∴ 1+a+b=1-10+1=-8