The expression which is used to represents the total number of stamps that Rose has is:
[tex]\dfrac{1}{2}x-7[/tex]
The number of stamp that Van has is: x
Now, it is given that:
Rose's stamp collection is 7 less than half of Van's stamp collection.
Half of Van's collection is: (1/2)x
and 7 less than this number is:
(1/2)x-7
Hence, the number of stamp with Rose is:
[tex]\dfrac{1}{2}x-7[/tex]