Terms are just names for objects inside the equation -- anything that isn't an operation. A coefficient the is the number a given term (variable) is being mulitpled by. In this case, -3 for y, and 1 for. x. We can deduce from this the start of the expression (x has no coeff. bc of multiplicative identity)
x - 3y
We know we are missing one term, and we also know that the third term cannot be constant, so it must be another variable. In this case I have chosen Z, in theory it shouldn't really matter but z is the best variable name in this case.
To find the area of a circle you need to find the radius. You find the radius by dividing the diameter by 2. So in this case, the radius is 14. Multiply 14 by pi and square your answer for the area.
