Question 152871


Count the sign changes of {{{f(x)=x^4+4x^3+6x^2+4x-1}}}


From {{{x^4}}} to {{{4x^3}}}, there is no change in sign


From {{{4x^3}}} to {{{6x^2}}}, there is no change in sign


From {{{6x^2}}} to {{{4x}}}, there is no change in sign


From {{{4x}}} to {{{-1}}}, there is a sign change from positive to negative 


So there is 1 sign change for the expression {{{f(x)=x^4+4x^3+6x^2+4x-1}}}. 


So there are 1 positive zeros



So the answer is a) 1