Question 29882
log(x)+log(x+15)=2
log(x(x+15)) = 2
log(x^2 +15x) = 2
assume log is to the base 10
10^2 = x^2 + 15x
x^2 +15x -100 = 0
(x + 20)(x - 5) = 0
x = -20
x = +5
check
log(-20)+log(-20+15)=2
log( (-20)(-5)) = 2
log(100) = 2
10^2 = 100
checks
and
log(x)+log(x+15)=2
log(5(5+15)) = 2
log(100) = 2
10^2 = 100
checks