write the particular equation of a quartic function that could, according to Descartes Rule of Signs have four positive zeros.
Descartes rule of signs states that if the coefficients of the polynomial changes sign n times, there is a maximum of n positive zeroes.
The number can be reduced by the presence of complex roots.
So to satisfy the given conditions, the coefficients must all alternate in sign AND have 4 real zeroes.
Hint: For example equations, expand
(x-1)(x-2)(x-3)(x-4)=0