What is the maximum number of negative real roots which can be formed for the following equation
x8+9x6+18x5−9x3+4x2+2x+1=0?
To find the number of negative real roots, we need to find the number of sign changes in f(-x)
To find f(-x) replace x by –x in the equation
f(−x)=x8+9x6−18x5+9x3+4x2−2x+1
Number of sign changes = 4
Maximum number of –ve real roots = 4