From their sum, the numbers are ' x ' and ' 8 - x ' .
From their product, x(8 - x) = 80 .
When you massage and manipulate this equation into the standard
quadratic form, you have
x² - 8x + 80 = 0 .
Applying the quadratic formula to tease out the solutions of this equation,
we find that they are
x = 4 + 64 i
and
x = 4 - 64 i