The mean of 4 numbers is 32. If three of the numbers are 15, 21, and 75, what is the value of the fourth number?

Daryl factors the polynomial p(x)=x3+x2−26x+24 to rewrite it as p(x)=(x+6)(x−4)(x−1). which equations must be true? there may be more than one correct answer. select all correct answers. p(1)=0 p(−4)=0 p(−1)=0 p(6)=0 p(4)=0 p(−6)=0