Question

Need to check my answer:
log x + log (x-3) = 1

i got x=1/2(3+-3)

Answer 1

how ?

Answer 2

doesn't seem correct...

Answer 3

\[x(x-3)=e^1\]

Answer 4

law of logs: log a + log b = log (ab)

log x + log (x-3) = 1
log x(x-3) = 1

x^2 - 3x = 10 (def. of log says log a = b when 10^b = a)

x^2 - 3x - 10 = 0

(x - 5)(x + 2) = 0

x = 5, x = - 2 (not possible b/c domain of log function is x>0)

Therefore, x = 5

Answer 5

the values should be 5 and -2

Answer 6

ah great