chris?

xy = 1064

(y-1)(x+19) = 1064
xy-x+19y-19 = 1064 [subtract xy = 1064 from this]
xy = 1064


Get 19y -x - 19 = 0
19y - 19 = x

[Get equation from above]
xy = 1064

[Substitute x for 19y - 19]

(19y-19)(y) = 1064
19y^2 -19y = 1064

19y^2 - 19y - 1064 = 0
[Lower down to~]

y^2 - y - 56

(y-8)(y+7) = 0
y = 8   y = -7

take y = 8 ~~
She bought 8 originally BUD

--extra work --
xy = 1064

1064/8 = x
x = 133