1. Which of the following statements is not always true? A. a + (-5) = -b + a
C. (a + b) + (-c) = a + [b + (-c)]
B. a - (-b) = (-b) - a
D. -(-a) = a

"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.

Given that ot =5, xt=12, and ox= 13 is xy tangent to circle o at t? explain.

How many quarts of a 50% solution of acid must be added to 20 quarts of a 20% solution of acid in order to get a 40% solution of acid?