Core 1 question

I am struggling to figure out what the second part of the question is asking.
https://gyazo.com/804486885d8a75569e525457e4455d55

What does it mean when it says "given the x axis is a tangent". I just do not know how to start. I have done the first part and got:
(x+4)^2+(y-2)^2=(20-k)^2 as the equation of the circle.

The x axis is a line where y=0.

If this line is a tangent to the circle, then just like tangents you are familiar with, there'll be a point where the tangent intersects with the circle.

Can you see why, and how to use this?

So do I sub in y=0 into the equation of the circle, expand everything and solve for K?

I am struggling to figure out what the second part of the question is asking.
https://gyazo.com/804486885d8a75569e525457e4455d55

What does it mean when it says "given the x axis is a tangent". I just do not know how to start. I have done the first part and got:
(x+4)^2+(y-2)^2=(20-k)^2 as the equation of the circle.

It means the y-component of the centre is equal to the radius.

yes

The x axis is a line where y=0.

If this line is a tangent to the circle, then just like tangents you are familiar with, there'll be a point where the tangent intersects with the circle.

Can you see why, and how to use this?

It means the y-component of the centre is equal to the radius.

so would that mean (20 - k)^2 = 2
then you would solve for k?

No, that would mean $\sqrt{20-k}=2$ and solve for k.

I am struggling to figure out what the second part of the question is asking.
https://gyazo.com/804486885d8a75569e525457e4455d55

What does it mean when it says "given the x axis is a tangent". I just do not know how to start. I have done the first part and got:
(x+4)^2+(y-2)^2=(20-k)^2 as the equation of the circle.

What exam board and paper is this from? Thanks

the tangent to the circle bit just means that the x-axis and the center are parallel

The x-axis and a point on the plane are parallel to one another...?