You multiply both of the equations until you have two of the same term the same like for example, say I have 4x and 5x. You want to multiply until both have the same number, so multiply 5x by four, then multiply 4x by five, and you will get 20x, then both of those cancel out and you will be left with the other variable, and you just solve like a normal equation.
You have the correct answer. It is choice A. Nice work.
I prefer using full circles because sometimes the arcs could be too small in measure to not go where you want them to. If you're worried about things getting too cluttered (a legitimate concern), then I recommend drawing everything in pencil and only doing the circles as faint lines you can erase later. Once the construction is complete, you would go over the stuff you want to keep with a darker pencil, pen or marker. You can also use the circle as a way to trace over an arc if needed.
Choice B is false as a full circle can be constructed with a compass. Simply rotate the compass a full 360 degrees. Any arc is a fractional portion of a circle.
Choice C is false for similar reasoning as choice B, and what I mentioned in the paragraph above.
Choice D contradicts choice A, so we can rule it out. Arcs are easier to draw since it takes less time/energy to rotate only a portion of 360 degrees. Also, as mentioned earlier, having many full circles tend to clutter things up.
1/18 can't be simplified because 1 cant be simplified. What ever happens to one side of the equation happens to the other, so nothing can happen to the 1 so nothing can happen to the 18
It cant be simplified