The sum of two numbers is 11 and their product is 128. find the numbers?

X+y=11

xy=128

x=11-y, so (11-y) y=128

11y-y²=128

y²-11y+128=0

use the quadratic formula to find y: y = (11+√391i) / 2 or y = (11-√391i) / 2

x = (11-√391i) / 2, or x = (11+√391i) / 2

so either there is an error in your question, or you have two unreal numbers:

(11-√391i) / 2 and (11+√391i) / 2