Respuesta :
Rearranging slightly you see:
3x^3+x+3x^2+1 now factor 1st and 2nd pair of terms...
x(3x^2+1)+1(3x^2+1)
(x+1)(3x^2+1)
3x^3+x+3x^2+1 now factor 1st and 2nd pair of terms...
x(3x^2+1)+1(3x^2+1)
(x+1)(3x^2+1)
hello : here is a solution
3x^3+x+3x^2+1 = 3x²(x+1)+(x+1) = (x+1)(3x²+1)
3x^3+x+3x^2+1 = 3x²(x+1)+(x+1) = (x+1)(3x²+1)