x(x+1)3+x(x+1)2+x(x+1)+x+1
=x(x+1)³+x(x+1)²+(x+1)·(x+1)
=x(x+1)³+x(x+1)²+(x+1)²
=x(x+1)³+(x+1)²·(x+1)
=x(x+1)³+(x+1)³
=(x+1)³·(x+1)
=(x+1)^4
x(x+1)3+x(x+1)2+x(x+1)+x+1
=x(x+1)³+x(x+1)²+(x+1)·(x+1)
=x(x+1)³+x(x+1)²+(x+1)²
=x(x+1)³+(x+1)²·(x+1)
=x(x+1)³+(x+1)³
=(x+1)³·(x+1)
=(x+1)^4