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.
Recall your d = rt, distance = rate * time.
notice, the distance are the same, say it was "d" miles.
and if car A is travelling at a speed of say "r" mph, then B is going at "r+15" mph.

how far is B going? well, r + 15.
Answer:
6 in 2.
Step-by-step explanation:
Area = √s(s-a)(s-b)(s-c)
= √6×(6 - 4)×(6 - 3)×(6 - 5)
= 6 inches 2.
They are both equivalent to 1, so they are equal.