Answer:
Do you really mean by -9 or cause I'm just confused but if you meant by 19 then this could help. I had my mom do whatever she could put as the answer so yeah
Explanation:
a*b=18 ____[1]
a+b=19____[2]
[2] a=19-b ___[3]
put [3] in [1]
(19-b)*b = 18
19b-b^2 = 18
b^2-19b+18 = 0
(b-18)(b-1) = 0
so b=18 or b=1
if b=18 then a=19-18=1
if b=1 then a=19-1=18
SO two factors are 1 and 18