We determine all zeros of the function y(x)=(x1)(x2)(x3)+6.

y(x)=0(x1)(x2)(x3)+6=0(x23x+2)(x3)+6=0x36x2+11x6+6=0x36x2+11x=0x(x26x+11)=0x(x26x+11)=0x=0 or x26x+11=0

We determine the zeros of x26x+11: D=(6)24111=8. Hence, this part has no zeros.

Consequently, the only zero of y(x) is x=0.