See, please, suggested decision:
When the line intersects the xy-plane, then parameter z=0, when does the xz - y=0 and when does yz, x=0. All the details are in attachment.
If it's possible, check arithmetic part.
14)
2(-3)² => 2(-3)(-3) => 2*9 = > 18
27+18-11 => 27 + 7 = > 34.
16)

17)

Answer:
The answer is 20
Step-by-step explanation:
(Edge2020)
Answer:
5
Step-by-step explanation:
n + m -2(m-m)
Combine like terms
n+m+2(0)
n+m
Let m=3 and n=2
2+3
5