Find all of the points of the form (x, −x) which are 1 unit from the origin.

To be 1 unit from the origin, points must lie on the unit circle, or 
x^2+(-x)^2=1
x=+/- sqrt(2)
If the point is restricted to the form (x,-x), then
x=sqrt(2)  => P1=(sqrt(2),-sqrt(2))
x=-sqrt(2) => P2=(-sqrt(2),sqrt(2))

Therefore there are two such points.

$22. if larry's profit were to minimize by one for every hour his store were to be closed, we would subtract 30 by 8.