Let us consider the statement \(b^n - b^{n-1} = b^{n-1} (b-1)\).

By quotient property of exponents,

\(b^n \div b^{n-1} = b\)

Subtracting 1 from both sides,

\((b^n \div b^{n-1}) - 1 = b - 1\)

\((b^n \div b^{n-1}) - (b^{n-1} \div b^{n-1}) = b - 1\)

\( (b^n - b^{n-1}) \div b^{n-1} = b - 1\)

Multiplying both sides by \( b^{n-1} \),

\(\boxed{b^n - b^{n-1} = b^{n-1} (b-1)}\)

Let \(b = \big\{x | x \in \mathbb{R}\big\}\).

If \(b = 0\), let \(n - 1 = \big\{x | x \in (1,+\infty)\big\}\).

## Comments

Sort by:

TopNewestYou can use the property of the exponents. Provided that \(b \neq 0\), \[b^n-b^{n-1} = b^{n-1}(\frac{b^n}{b^{n-1}}-\frac{b^{n-1}}{b^{n-1}})\] \[b^n-b^{n-1} = b^{n-1}(b^{n-(n-1)}-b^{(n-1)-(n-1)})\] \[b^n-b^{n-1} = b^{n-1}(b^1-b^0) = b^{n-1}(b-1)\] \[Q.E.D.\] – Kay Xspre · 1 year, 6 months ago

Log in to reply

– Adriel Padernal · 1 year, 5 months ago

Thank you very much, I have now provided more supportive evidence for my theorem.Log in to reply

– Calvin Lin Staff · 1 year, 5 months ago

Kay's comment isn't just "supportive evidence". It is a proof of the statement which you stated.Log in to reply

– Adriel Padernal · 1 year, 5 months ago

Thank you, I understand. At first, I was doubtful in a way that others might correct me for calling it "proof" so I decided to call it "supportive evidence."Log in to reply

It can take a while for you to become familiar with mathematical rigor. We all have to start somewhere, and I'm glad that you're learning! – Calvin Lin Staff · 1 year, 5 months ago

Log in to reply

Note that you have not proven the theorem. You have only demonstrated that it is true in 5 specific cases. – Calvin Lin Staff · 1 year, 6 months ago

Log in to reply

– Adriel Padernal · 1 year, 6 months ago

Thank you for commenting your thoughts on this. This is my first note on Brilliant. Thank you again.Log in to reply