This is a very hard question but, i am a very hard man.
The only error you made is on problem 3. Everything else is correct. Nice work.
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Here is how to solve problem 3
Plug x = 1 into the equation and solve for y
-3x + y = 1
-3*1 + y = 1 ... replace x with 1
-3 + y = 1
y - 3 = 1
y - 3 + 3 = 1 + 3 .... add 3 to both sides
y = 4
<h3>The answer is 4</h3>
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Verifying the answer:
Plug (x,y) = (1,4) into the equation. Both sides should be the same number after simplifying both sides.
-3x + y = 1
-3*1 + 4 = 1 ..... replace x with 1; replace y with 4
-3 + 4 = 1
1 = 1
The answer is confirmed.
If you were to graph -3x + y = 1, which is equivalent to y = 3x+1, you'll find that the point (1,4) is on this line.
Given rational expression is:
Now we can simplify this by factoring as shown below:
Hence final answer is 
4 x 1 thousand (1000) = 4000
21 x 1 ten (10) = 210
4000
+ 210
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4210
=4210 (four thousand-two hundred and ten
The answer is =324°*(\pi )/(180<span>°</span>)
