Evaluating an expression consists of just replacing the letter by its value and do the calculus.
We have the expression 14b - 513. And by hypothesis, b = 44.
So just replace b by 44.
14b - 513 = 14*44 - 513 = 616 - 513 = 103.
So 14b - 513 = 103 (answer b) when b = 44.
Hope this helps! :)
