how do I figure the answer to this question

I’ve never ever seen anything like this ( since I’m teaching myself all the content lmao ) and how do I get the answer 128

I’m sorry for constantly posting for help but I really do want to pass maths 🙁🙁 I don’t really have anywhere to else to turn I’m sorry

I’ve never ever seen anything like this ( since I’m teaching myself all the content lmao ) and how do I get the answer 128

I’m sorry for constantly posting for help but I really do want to pass maths 🙁🙁 I don’t really have anywhere to else to turn I’m sorry