what two numbers have the product of -78 and the sum of -3.
x+y = -3 and xy= -78
y = -3-x
sub into the 2nd
x(-3-x) = -78
-3x - x^2 + 78 = 0
x^2 + 3x - 78 = 0
x = (-3 ± √321)/2 = appr 7.458 or -10.458
then the corresponding y = -10.458 or 7.458
we have "symmetric " answers
the two number are appr. 7.458 and -10.458
check: 7.458 + (-10.458) = -3
(7.458)(-10.458) = -77.9958 , not bad