Why are these rows equivalent? are they even equivalent? please tell me the right answer. 7a+5b−3a+4b
7a+5b+(-3a)+4b

"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.

Multiplying an even number of negative numbers gives an answer that is choose from:

If m 17 27 90 63 ** picture is attached