Step-by-step explanation:
I don't know if the first set of numbers is all in one set, but I'll do my best to give you an answer.
Really all you need to do is use PEMDAS for the first question.
(Parentheses, exponents, multiply, divide, add, subtract. In that order)

Then to simplify that fraction next to it, notice that 0.018 is 3x 0.06.
that's a 3:1 ratio, so it ends up simplifying to this:

Lastly, to solve the division of that fraction. If you divide by a fraction, you multiply whatever it's dividing by its inverse.
So...

Answer:
The rate of change of the volume of the cylinder at that instant = 
Step-by-step explanation:
Given:
Rate of increase of base of radius of base of cylinder = 7 mm/hr
Height of cylinder = 1.5 mm
Radius at a certain instant = 12 mm
To find rate of change of volume of cylinder at that instant.
Solution:
Let
represent radius of base of cylinder at any instant.
Rate of increase of base of radius of base of cylinder can be given as:

Volume of cylinder is given by:

Finding derivative of the Volume with respect to time.

Plugging in the values given:


Using 

(Answer)
Thus rate of change of the volume of the cylinder at that instant = 
two points are (0,0) and (100, -800)
m = (y2-y1)/(x2-x1) = (-800-0)/(100-0) = -8
point slope form of the line is
y-y1 = m(x-x1)
y-0 = -8 (x-0)
y=-8x
this is in slope intercept form now
y=-8x