The product of (3 + 2i) and a complex number is (17 + 7i)

 Of course you're looking for the ratio: (17+7i)/(3+2i). To get a clear number, you need to get a real number at the denominator -- and it so happens that the product of two complex conjugates is a real number. So, you multiply the denominator and the numerator by the conjugate of 3+2i. The denominator becomes 13 and the numerator becomes 51 + 7i. Hence, the multiplier is 51/13 + 7/13 i. 

As a side note, while you probably knew how to factor a difference of squares, I just showed how to factor a sum of squares: a^2 + b^2 = (a + bi)(a - bi). That holds because i^2 = -1.

Hope this's useful/helpful