Answer:
C. f(-1) =12
Step-by-step explanation:
f(x)= 3x^2+9
Let x=-1
f(-1) = 3(-1)^2 +9
= 3(1)+9
= 3+9
= 12
f(-1) =12
Let the boy be B and the girl be G
there are six possible outcomes
BGG, GBB, GBG, BGB, BBB, and GGG
therefore the probability of getting one boy and two girls is

also the probability of getting 3 girls is