It should be x=11 instead of x=-11, so
he is not correct because he made a sign error.
<span>the dimensions are 15 inches long and 12 inches wide</span>
The answer is 36/49.
You take the second fraction and flip it (it will be 12/14) and you multiply straight across. You get 72/98. You simplify it by finding it's greatest common factor (in this case it is 2) so you divide it the numerator and the denominator by 2. You get 36/49.