Question

log (x + 2) + log (x - 2) = log 21 then x(Answer should be 5)

Answer 1

Step-by-step explanation:

5 not -5

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Answer 2

Answer:

5 or -5

Step-by-step explanation:

log a + log b = log ab

hence

log (x + 2) + log (x - 2) equals log (x square - 4)

(a+b × a-b) equals a square minus b square

now given answer

21

hence x square - 4 equals 21

hence x square equals 25

therefore x equals 5 or -5

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