Question 4
LogarithmsGiven that log4(y − 1) + log4(½x) = 1 and log2(y + 1) + log2x = 2, solve for x and y respectively.
- A.2, 3
- B.3, 2
- C.−2, −3
- D.−3, −2
Show the answer and explanation
Answer: C (−2, −3)
Explanation
The first equation gives (y − 1)(x/2) = 4, so xy − x = 8. The second gives x(y + 1) = 4, so xy + x = 4. Subtracting gives 2x = −4, so x = −2 and then y = −3.