Question 1194290
.
<pre>

Let x be the number exactly half way between our two numbers.


Then the two numbers are x+4 and x-4;  their product is (x+4)*(x-4) = x^2 - 16.


So we have this equation for x

    x^2 - 16 = 209

    x^2 = 209 + 16 = 225.


Thus  x = {{{sqrt(225)}}} = +/- 15/


The problem has two solutions.


One solution is the pair  (15-4,15+4) = (11,19).


Another solution is the pair  (-15-4,-15+4) = (-19,-11).
</pre>

Solved.