Expand & simplify
(9x - y) (9x + y)

(40 points) i need some . an answer definition is appreciated as well.

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?