so xy=-1040 and x+y=109
a negative times a positive = a negative so x or y must be negative and only one
so xy=-1040
x+y=109
subtract x from both sides
y=109-x
subsitute y=109-x into xy=-1040
x(109-x)=-1040
109x-x^2=-1040
add x^2 to both sides
109x=-1040+x^2
subtract 109x from both sides
x^2-109x-1040=0
put it in the quatdratic formula and get
x=[{(7721)^(1/2)}+109]/2 or [{(7721)^(1/2)}-109]/2
