Answer:
Initially, Anglea has $6*w in total.
Then she buys N books, at $17 each, then the total cost of the books is: N*$17
After that, she had left $w.
a) This means that:
$6*w - N*$17 = $w
Now we can isolate the variable N in one side of the equation:
N*$17 = $6*w - $w = $5*w
N = ($5/$17)*w
N = (5/17)*w
That is the equation that tells the number of books Angela bought in terms of w.
b) Now we just need to replace the w by 34 in the above equation:
N = (5/17)*34 = 10
If w = 34, Angela bought 10 books.
