foodstamp
Attached is the question.
I don't fully understand what statement 1) tells us (not sure why the explanation about statement 1 is correct).
Thanks!
I say that the answer is B.
First of all, when you look at the equation \((x-a)^2 + (y-b)^2 = 16\), the radius of the circle is 4. Also, the center of the circle is at (a,b). So we need to know the value of a and b (although a alone will be sufficient to help us answer this question) in order to figure out whether it's location is still within reach to the y-axis when taking its radius into consideration:
(1) \(a^2 + b^2 > 16\) ---> we can not determine the exact values for a and b because we can't tell whether they're positive or negative. Even if we do manage, the choices are endless
(2) \(a = |b| + 5\) ----> we know that |b| can be either a zero or positive. So when you rearrange this equation to:
\(a - 5 = |b|\), you know that the result must also be either a zero or positive. In order for this to be true, a must be at least a 5. When our value of a is at least a 5 and then we look at the center of the circle to be (a,b), the x-axis of 5 is longer than the length of the radius of 4, therefore the answer is no: the circle does not intersect the y-axis.
Answer is B.