Which of the following equations has only one solution?

x^2 = 9
x(x - 1) = 9
x^2 - 6x + 9 = 0

Provide an example of a trigonometric function and describe how it is transformed from the standard trigonometric function f(x) = sin x, f(x) = cos x, or f(x) tan x using key features.

"you know, playing tennis is healthier than watching a tennis match on television," katya remarked to her couch potato brother. in this sentence, healthier is a/an a. superlative. b. comparative. c. positive form. d. adverb.

What is always true when two whole numbers are subtracted?