t = 9 + s is the expression for number of pages in terry's essay
Solution:
Given that, Terry's essay has 9 more pages than stacey's essay
Let "s" be the number of pages in Stacey essay
Let "t" be the number of pages in terry essay
To find: Expression for the number of pages in terry's essay
From given statement,
Terry's essay has 9 more pages than stacey's essay
Which means, number of pages in terry essay is 9 more than number of pages in Stacey essay
Therefore,
Number of pages in terry essay = 9 + number of pages in Stacey essay

Thus the expression for number of pages in terry's essay is found