Our product is 72. the difference between us is 1. what numbers are we?

Xy = 72
x - y = 1
x = 1 + y

(1+y)y = 72
y + y^2 = 72
y^2 + y - 72 = 0
(y-8)(y+9) = 0
y = 8 , y = - 9

x = 1 + 8
x = 9

y = 8

i am a mathematics teacher. if anything to ask please pm me

300b(x) is graphed by the functio