According to Descartes' rule of signs, how many possible negative real roots could the following polynomial function have?

f(x)=3x⁴-5x³+5x²+5x+2

A. Three
B. Three or one
C. Two or zero
D. One

Question

According to Descartes' rule of signs, how many possible negative real roots could the following polynomial function have?

f(x)=3x⁴-5x³+5x²+5x+2

 		A.	Three
 		B.	Three or one
 		C.	Two or zero
 		D.	One

ash2326 · Answer

let's find f(-x)
$$f(-x)=3x^4+5x^3+5x^2-5x+2$$
let's find the no. of sign changes
here it's 2
so max no. of negative roots 2 
option C