A broken calculator has only the keys:
+(addition), -(subtraction), /(division), x(multiplication), =(equals)
It is a simple calculator that can do one binary operation at a time.
The only functional digit is 7.
How is it possible for 34 to appear in the readout in the fewest number of keystrokes?
1. Performing as many operations as possible is allowed.
2. The digit 7 may be reused, that is expressions like 777x77 or, 7777+7 in a given operation is allowed.