These are the functions that return a value after their completion. A fruitful function must always return a value to where it is called from. A fruitful function can return any type of value may it be string, integer, boolean, etc. It is not necessary for a fruitful function to return the value of one variable, the value to be returned can be an array or a vector. A fruitful function can also return multiple values.
The possible solution for this kind of problem is to equate the said equation base on what is ask in the problem. The design equation is use to get the Voltage out of a said circuit, thus, without any value of resistance, the left and side value of the equation should be the same, and the said problem is generally incomplete. With that, the possible answer would be -53.
Try restarting the PC. I have the same issue on Windows 10 sometimes generally its a network error because Windows 10 has a lot of internet required features...