-21x^3 - 8x^3 = -29x^3
-7/4x^(1/2) - 0 = -7/4x^(1/2)
-6x^(1/4)
-12x^(-1/2)
12x^(-1/4)
14x^4
Therefore, the correct option is the 2nd one.
The original can be rewritten as

. Because i^2 is equal to -1, we can replace the -1 in each radicand with i^2, like this:

. Now, i-squared is a perfect square that can be pulled out of each radicand as a single i.

. 24 has a perfect square hidden in it. 4 * 6 = 24 and 4 is a perfect square. So let's break this up, step by step.

and then

. We will now multiply the i and the 2i, and multiply the square root of 6 times the square root of 6:

. 36 itself is a perfect square because 6 * 6 = 36. So we will do that simplification now.

. Multiplying the 2 and the 6 gives us

. But here we are back to the fact that i-squared is equal to -1, so 2(-1)(6) = -12. See how that works?
You can go through the effort of determining the zero of the function analytically and evaluating an analytic expression for the derivative at that point, or you can let a graphing calculator do that heavy lifting. Since the numbers have to be "nice" for your equation to have the desired form, it is easy to know what to round to in the event that is necessary (it isn't).
We find the positive zero-crossing at x=2, and the slope of the curve at that point to be 8. Thus the line will have slope -1/8 and can be written as
.. x +8y -2 = 0
The correct statements are as follows:
A point's location on the coordinate plane is indicated by an ordered pair, (x,y).
// Hope this helped, comment below for further clarification //