Answer:
The answer is 13.
Explanation:
Angle ABC and PQR are equivalent, although angle PQR is just scaled down by a factor of 9. Line CA is 54, line PR is 6, 54/6=9. So, line PQ has to be equal to 9 because 81/9=9. So you input all values into the expression until you get the product of 9.
Work: 2(13)-17=9, so 13 is your answer.