Question

C++ what is wrong with my equation?

Answer 1

This (simplified) piece of code seems to work:

int OriginalNum;

int AnswerNum;

cout << "Insert your number: ";

cin >> OriginalNum;

AnswerNum = 201*OriginalNum;

cout << "The answer is:";

cout << AnswerNum;

If I copy what visible in your screen, the compiler complains about the variable OriginalNum not being declared. Try to paste my code and see if you have any issue.

Note: the expression OriginalNum*2*100 + OriginalNum is simply a multiplication by 201!

In fact, you have

$x\mapsto 2x \mapsto 2x\cdot 100 = 200x \mapsto 200x+x = 201x$