Answer:
b), c), d)
Step-by-step explanation:
Like terms are terms that have same variables with same powers.
a)
[tex]3x^2,3x^3[/tex] have same variable [tex]x[/tex] with different powers.
So, [tex]3x^2,3x^3[/tex] are not like terms.
b) [tex]-7xy,-9yx[/tex]
Power of [tex]x[/tex] in each of the terms = 1
Power of [tex]y[/tex] in each of the terms = 1
[tex]-7xy,-9yx[/tex] are terms that have same variables [tex]\{x,y\}[/tex] with same powers.
So, [tex]-7xy,-9yx[/tex] are like terms.
c) [tex]8b,-0.5b[/tex]
Power of [tex]b[/tex] in each of the terms = 1
[tex]8b,-0.5b[/tex] are terms that have same variable [tex]b[/tex] with same power.
So, [tex]8b,-0.5b[/tex] are like terms.
d) [tex]-p^2q^2,(pq)^2=p^2q^2[/tex]
Power of [tex]p[/tex] in each of the terms = 1
Power of [tex]q[/tex] in each of the terms = 1
[tex]-p^2q^2,(pq)^2[/tex] are terms that have same variables [tex]\{p,q\}[/tex]with same powers.
So, [tex]-p^2q^2,(pq)^2[/tex] are like terms
