So...the diameter is increasing at a rate if 2cm/minute, therefore the radius (1/2 the diameter) is increasing at half the rate. You will learn how to calculate the rate of change at a specific point in time in calculus.
Think of when If you cross two lines you get a point where they meet
A point is a solution.
So if the lines never cross, then they would have no point, or A, No Solution
12x-4y=16
Isolate Y:
Subtract 12x from both sides
-4y=-12x+16
Divide by -4
y=3x-4
Therefore the slope is 3
