For each expression given below, carry out the tasks mentioned in parts (i) to (iii):
(a) 6y2+0y
(b) −3a4+2a2−5
(c) 9
(d) 2p3−7p+21
a. (i) Rewrite the expression, if necessary, so that it contains no zero–coefficient terms and is arranged in descending powers of the variable.
b. (ii) State the number of non-zero terms in the rewritten expression.
c. (iii) Classify the expression obtained in part (i) as a monomial, binomial or trinomial, and write its degree.