The function g(x) is defined by . If g(x)=12, then which of the following is true about the value of x?
Answer Choices
Correct answer marked belowSee the full step-by-step explanation
You can see the correct answer above. Sign in for free to unlock the complete worked solution.
Track your performance and improve
Get detailed analytics, unlock full explanations, and move up difficulty tiers as you practice.
Official Explanation
Taking logarithms or recognizing that implies plus some additional factor from the 4.…
Read the full explanation
Sign in for free to see the complete step-by-step solution to this question.
Can you explain more?
Amazing
Thank for sharing!!!
Can someone explain it other way?
Thankss
Great question!
Set 120 - 3^x = 12 and solve. 3^x = 108. 3^4 = 81 and 3^5 = 243, so x has to be somewhere between 4 and 5. That lands in (B).
Ohh I made the mistake of thinking 3^4 = 108 for a second lol. It's 81, right?
thanks, this one was pretty quick once you get 3^x alone
Wait why is the answer range 3<x<=6 and not just x=4 or 5? Is it because they're asking which interval x falls in?
Yep, the answer choices give ranges instead of exact values, so you just have to figure out which range contains the actual x.
What it tests
Your ability to manipulate linear and quadratic expressions, substitute unknowns, and solve equations under time pressure.
Common trap
Losing a sign when moving terms across the equals sign, or dividing both sides by a variable that could equal zero.