When you take a look at this, it does not come across as a tricky algebra problem at all. But think again. This problem is very similar to the algebra problem that I solved about a while back, in that it appears simpler on the surface (not in terms of approach to solution).
You are provided with an equation that features a fraction on the left-hand side (LHS) and a singular constant term (2) on the right-hand side (RHS). All four terms on the LHS are exponential terms with the same unknown exponent (x). Your job is now to figure out the integer value(s) for βxβ that would satisfy the given equation.
How would you proceed?
Spoiler Alert
If you wish to solve this equation on your own, please go ahead and do it now. Once you are done, you may choose to come back and read the rest of this essay. Beyond this point, I will be explicitly discussing the solution(s) to this equation.
This essay is supported by Generatebg
A Crude Approach to Solving the Tricky Algebra Problem
Let us start with a crude, yet potentially effective approach to solving this equation β the plain old trial-and-error method. Let us start by substituting βxβ with 0 and see what happens:
On the LHS, we end up with 0/0 and on the RHS, we end up with 2. In mathematics, 0/0 is βundefinedβ. If you wish to understand the reasoning behind this in detail, check out my essay on what really happens when you divide zero by zero.
In this case, when we have a defined value on the RHS (2) and an undefined value on the LHS (0/0), we have no solution. Why donβt we try our luck by substituting βxβ with 1 and see what comes out?
Bingo! We have our first valid integer solution on just our second try! This equation is perhaps not so tricky after all. Before we go off celebrating, we need to look at the bigger picture.
Sure, we have now arrived at a valid integer solution. But how do we check for other integer solutions without laboriously brute-forcing integer-substitutions into infinity? Well, we need to turn to algebra for that.
A Refined Approach to Solving the Tricky Algebra Problem
Reducing Complexity
When I look at the equation, I see potential for simplification. Often times, when we employ algebra, we aim to simplify equations to the point where we start extracting some sort of meaning out of them. In other words, we are going to try and simplify something we donβt understand into something that we do understand.
Let me start by writing out the terms in the numerator and the denominator of the LHS expressed in relation to common terms and then factor them out.
Now, the terms inside the parenthesis on the numerator of the LHS represent a difference between squared terms. In such a case, we can make use of the following algebraic identity:
aΒ² β bΒ² = (a+b)*(a-b)
If we multiply both sides by 3^x, we get the following result:
It may not be apparent yet, but this is a form that we can work with. Letβs find out how.
Analysing the Positive Integer Line
So far, we know that βx = 0β is not a valid solution and βx = 1β is a valid solution. If we are to look for positive integer solutions further, we need to search in the domain of βxβ₯2β. In this domain, the following situation comes into play:
We have an even result on the LHS and an odd result on the RHS. This scenario means that there exists no other valid solution for the given equation on the positive integer line (other than βx = 1β).
Having come this far, the only other direction we can go in is along the negative integer line.
Analysing the Negative Integer Line
To explore the negative integer line, let us consider βx = -nβ, where βn β₯ 1β. When we plug β-nβ in place of βxβ, we get the following:
If we choose to cross multiply the terms on both sides of the equation, we arrive at the following result:
This time, we end up with an odd term on the LHS and an even term on the RHS. This scenario means that there exists no valid solution for this equation on the negative integer line.
Therefore, we can say with certainty that the only valid integer solution for the given equation is βx = 1β.
Source: IMOMath
If youβd like to get notified when interesting content gets published here, consider subscribing.
Further reading that might interest you: How To Really Solve This Tricky Algebra Problem? and How To Really Benefit From Curves Of Constant Width?
If you would like to support me as an author, consider contributing on Patreon.
Comments