Question 968826
logx +log(x-21) = 2
use log rule log(xy) = log(x) + log(y)
log (x^2 -21x) = 2
use definition of log
x^2 -21x = 10^2
x^2 -21x -100 = 0
factor equation
(x-25)*(x+4) = 0
x = 25 or -4