How many integers n is 7n+1 divisible by 3n+5?
What exactly is this question asking?
What's the set up?
You have made two errors. First, you included n = 2, which does not work
because the fraction equals 15/11, a noninteger. Second, you did not include the
solution of n = 9, which makes the fraction 64/32 = 2.
Also, I did not catch your typo in the numerator of your fraction.
Instead of (7n - 1) that you wrote, it is supposed to be (7n + 1).
However, the expression for n in terms of x right below that is correct.