This is valid through the law of syllogism. If you swap lines 1 and 2, then you'll have this argument:
If I step on a beehive, then I will get stung.
If I get stung by a bee, then it will hurt.
Therefore, if I step on a beehive, then it will hurt
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So it's like connecting a chain together. Point A (stepping on the hive), leads to point B (getting stung), which leads to point C (getting hurt). We can take a shortcut to bypass point B to jump from A to C in one step. Check out the attached image for a visual of what I'm referring to.
Answer:

Step-by-step explanation:
27 is a perfect cube for
and 729 is a perfect cube for 
now you can pull out the numbers from under the root, for t (divide the exponent by 3)

now simply to 
Answer:
D. 62 square feet
Step-by-step explanation:
uz + wx + (v+z)(y-u-w)
6*3 + 4*6 + (7+3)(12-6-4)
18 + 24 + 20 = 62