Hello,
Please, see the attached file.
Thanks.
Answer:

Step-by-step explanation:
According to the "rules" of significant figures, all the zeroes to the right of the final non-zero number are <em>not </em>significant, unless there is a decimal point.
We are given the measurement:
84,000 kg
If there was a decimal point (84,000.0 kg), then there would be 5 significant figures.
Since there isn't a decimal point, all 3 zeroes to the right of the number 4 aren't significant. The 8 and 4 are significant, so there are <u>2 significant figures</u>.
Answer: N=15
Step-by-step explanation:
3n+32=77
subtract 32 from 77 which you give you 45
3n=45 then divide it by three
so 45/3=15 so N=15
N is 2/3 because 1 minus 1/3 is 2/3