Answer:
either of Step 3 or Step 4
Step-by-step explanation:
At Step 3, -1 is added to both sides of the equation. Technically, this is correct (not an error), but it does not lead to a solution to the equation (so, could be considered to be an error). Adding +1 to both sides of the equation would lead more directly to a solution.
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At Step 4, x -1 -1 is simplified to x. This is an error, as the correct simplification is x-2, so the equation after this step should read x-2 = 5. If Step 3 had been executed by adding +1 to both sides of the equation, then the simplification here would be x=7.
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Answering "why" someone does something is always tricky. One can project one's own interpretation onto the actions of others, but one never really knows whether that is accurate or not.
The "why" in this case could go back to the motivation of the problem's author, which may be to see if the student can recognize that the opposite of -1 is +1, or that the sum -1-1 is not zero.
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My guess is that Step 3 is considered to be the erroneous step, and that choosing Step 4 will get you into a losing argument with your grader.
Answer:
300000
Step-by-step explanation:
An easy way to solve this is find 6x5 which is 30 and then add all of the 0s at the end from the equation which is 4 zeros
Answer:

Step-by-step explanation:
Total Volume of Water = 
Volume drunk by James =
Volume drunk by Simon =
Volume drunk by Matthew = 
Volume drunk by Gilbert =
Total Volume Drunk (i.e. The Sum) = 
Volume of water Left = Total Volume of Water-Total Volume Drunk
= 
Use a factor<span> tree to express </span>60<span> as a </span>product<span> of prime </span>factors<span>. So the prime factorization of </span>60<span> is 2 × 2 × 3 × 5, which can be written as 2 </span>2<span> × 3 × 5.</span>
567 = 500+60+7
4*567 = 4*(500+60*7)
4*567 = 4*500 + 4*60 + 4*7 ... see note below
4*567 = 2000 + 240 + 28
4*567 = 2268
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note: multiply the outer term 4 by each term inside the parenthesis to use the distributive property. The general distributive property is a*(b+c) = a*b+a*c. This can be extended to a*(b+c+d) = a*b+a*c+a*d. You can have as many terms as you like inside the parenthesis.