log(x + 4) + log(3x + 2) = log( (x + 4)(3x + 2) ) = log( 3x2 + 14x + 8 )
log(100) - 2log(2) = log(100) - log(22) = log(100) - log(4) = log(100/4) = log(25)
Combining: log( 3x2 + 14x + 8 ) = log( 25 )
---> 3x2 + 14x + 8 = 25
---> 3x2 + 14x -17 = 0
---> (3x + 17)(x - 1) = 0
---> either 3x + 17 = 0 or x - 1 = 0
x = -17/3 or x = 1
The answer -17/3 doesn't check; the answer 1 does.