Alan

Use:  22500/x = 358

Rearrange to get x = 22500/358 ≈   62.85 kg

(-6)^(1/2) = (-1)^(1/2)*6^(1/2) = i*6^(1/2)

So the real part of 7 - (-6)^(1/2) is just 7 and the imaginary part is -6^(1/2)

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Put the argument in brackets and then raise to the power  tan(x)^(-2)  

That's if you want 1/tan(x)^2.

You can type the following into the calculator here:

and get the following response

The problem statement is:

 How compressed is a spring with a constant of 500 N/m if a force of 40 N is applied to it?

The answer below it seems to have invented numbers that don't relate to those in the question!!

To answer the question use Hooke's law:  Force = spring constant*extension, so

extension = 40/500 = 0.08m

This is marked as incorrect in the answer box because there is another piece of information that specifies the answer is to be given to the nearest tenth, so extension ≈ 0.1

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Like so:

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If x^3 = 14 then x = 14^(1/3) ≈ 2.41

First simplify slightly by dividing through by 4 to get:  625 - 100x + 3x^3 = 0

This doesn't factorize nicely, so, if you are only interested in real number solutions, first plot a graph then use a numerical approach, such as Newton-Raphson:

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Here:

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Use the on-line random number generator at https://www.random.org/integers/ for example.