Tom buys a pen holder for $5 and 10 pens for $1 the sales tax for the whole purchase is $3. what percent was the sales tax?

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

Which of the following equations is of the parabola whose vertex is at (2, 3), axis of symmetry parallel to the y-axis and p = 4? a.)y-3 = 1/16 (x-2)^2 b.)y+3 = -1/16 (x+2)^2 c.)x-2 = 1/16 (y-3)^2

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible