Let the numbers be x and y
So, xy = 90
x+y = -27
2xy = 180
-2xy = -180
(x+y)² = x²+y²+2xy
(-27)² = x² + y² + 180
729 - 180 = x² + y²
x² + y² = 549
(x-y)² = x² + y² -2xy
= x²+y² -180
= 549 - 180
= 369
x - y = √369 = 19.21
x + y = -27
2x = -7.79 ≈ -7.8
x = -7.8/2 = -3.9