Question 1033854
Same problem, different numbers.
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log(x) + log(x+21) = 2
 log(x*(x+21)) = 2 = log(100)
 x^2 + 21x - 100 = 0
 (x+25)*(x-4) = 0
 x = -25 *** not allowed --> log of negative number
 x = 4