log(x,5)+log(2x+3,5)=1,how do I find x?
log5(x) + log5(2x + 3) = 1
Since logs are added when the original problem was multiplied, going backwards we have:
log5[ x · (2x + 3) ] = 1
log5( 2x2 + 3x ) = 1
Writing the log in exponential notation:
2x2 + 3x = 51
---> 2x2 + 3x = 5 ---> 2x2 + 3x - 5 = 0 ---> (2x + 5)(x - 1) = 0
---> Either 2x + 5 = 0 or x - 1 = 0
---> Either x = - 5/2 or x = 1
Since log5(x) is undefined if x is a negative number, the value -5/2 must be ignored; thus the answer is x = 1
log5(x) + log5(2x + 3) = 1
Since logs are added when the original problem was multiplied, going backwards we have:
log5[ x · (2x + 3) ] = 1
log5( 2x2 + 3x ) = 1
Writing the log in exponential notation:
2x2 + 3x = 51
---> 2x2 + 3x = 5 ---> 2x2 + 3x - 5 = 0 ---> (2x + 5)(x - 1) = 0
---> Either 2x + 5 = 0 or x - 1 = 0
---> Either x = - 5/2 or x = 1
Since log5(x) is undefined if x is a negative number, the value -5/2 must be ignored; thus the answer is x = 1