You can put this solution on YOUR website!
You apparently have done everything correctly so far. If you have written the problem correctly, there is a chance that the book is wrong.
You have correctly identified PQ as 11 units long. Therefore, you correctly said that side SR must also be 11 units long. And since SR equals 7x-3, you correctly set 7x - 3 equal to 11 units and solved this equation to find that x=2 units.
You did not explain much further, but QR is given as 3x-3. Since you now know that x=2, you can substitute to find that:
This simplifies to:
and this tells you that QR = 3
But the opposite sides of a rectangle are equal in length. Since side PS is opposite to side QR, its length must also be 3.
In summary you have PQ = 11, QR = 3, SR = 11, and PS = 3. If you add these four lengths you find that the perimeter is 28 units long.
If this doesn't agree with the book answer, you either provided some wrong information on the problem or the book answer is wrong. Go through the above work and see if it tracks exactly with the problem information from the book. If it does, then the publisher of the book made an error. [Believe me, it wouldn't be the first time a publisher made a mistake.]