Which of the following is not a polynomial identity?
a. a^3-b^2= (a-b)(a^2+ab+b^2)
b. (a+b)^2= a^2+2ab+b^2
c. a^2(b+c)= a^3(b/a+c)
d. (a^2+b^2)(c^2+d^2)=(ac-bd)^2+(ad+bc )^2

Kilgore trout creates a new scale to diagnose depression. however, his scale only assesses one symptom of depression while ignoring others. which of the following is his new scale most likely lacking? a) test-retest reliability b) discriminant validity c) criterion validity d) alternate-forms reliability e) content validity f) none of the above