<em><u>The equation can be used to find the actual length of Gregory's room is:</u></em>

<em><u>Solution:</u></em>
Given that,
The scale that he uses is:
1 cm : 4 feet
On this drawing, the room is 3 cm long
Let "x" be the actual length of room
Therefore,
1 cm : 4 feet
3 cm : "x" feet
This forms a proportion. Therefore,

Therefore, Option C is correct
Given that,
Rob chose A as the correct answer. Which is,

But option A is wrong
So, Rob made a mistake in measuring the equivalent ratio, it should be 
The answer is the 3rd option. The equation obtained by switching….
Answer:
C. trace metals released during combustion
Step-by-step explanation:
These environmental costs can be associated with natural gas:
- pipelines built through environmentally sensitive areas
- the release of methane into the atmosphere
- groundwater contamination
- degradation of the land due to drilling techniques
Trace metals released during combustion can be associated with coal or biomass
1.
subtract 6.1 from both sides
1.4x + 6.1 -6.1 = -7.9 -6.1
1.4x = -14
2.
Divide both sides
1.4x/1.4 = -14/1.4
x = -10