
Find the reciprocal of 4 and multiply.

Multiply the numerators and denominators together:
Hey there!
A parent function is the most basic function in any group of functions. For example, f(x) = x^2 is the parent function for quadratic functions, and y = x is the parent function for linear functions. When there's nothing added, subtracted, multiplied, or divided to the function.
For A, we see that we're multiplying 2 times 3^x, and since this is not any alternation of any parent function or any parent function in particular, we can rule it out.
For B, we see that 3 is being added to x^2, so it cannot be a parent function.
For C, we see that 2 multiplied to e, therefore it cannot be the mot basic function.
Finally, for D, we see a function that looks similar to the quadratic parent function and is very simple itself. Any alterations to this is any other quadratic function
Your answer is D.
Hope this helps!
Not getting in to too much details but basically
Area of half circle - area of triangle
3.14r^2-1/2bh
r=6 b=12 h=6
There 6000 L of liquid left in the tank at 30 min left