Answer:
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<em>The last option matches the correct solution</em>
Step-by-step explanation:
<u>Equation Solving</u>
We have the following equation:
And it's required to solve it for r.
Solving this equation needs to perform some operations to have the r isolated from any other variables or constants.
It can be done by conveniently operating on both sides as follows:
Eliminate the denominator by multiplying by 3:
Move to the other side by dividing by :
Swapping sides to have r at the left side:
Finally, take the cubic root and leave r alone:
The last option matches the correct solution