Question

Prove 9n - 1 is divisible by 8.

The first two steps will be provided. For step 3, match the right and left sides of the equation to prove the statement.

Step 1: When n = 1, 9n -1 = 91 - 1 = 8. Eight is divisible by 8, so the equation is true for n = 1.

Step 2: Assume that 9k-1 is divisible by 8 for some positive integer, k. This means that there is a whole number r such that 9k-1 = 8r.

Step 3: Show that the statement n = k + 1 is true.

9k - 1 =


9k =


9(9k) =


9k+1 =


9k+1 - 1 =


9k+1 - 1 =
@mathmale @YanaSidlinskiy
I am so confused!

Answer 1

I'll attach a file that I have written to prove another question.. You can compare it with this..

let me know if you need any assistance...

Answer 2

You have to,now,prove, what @YanaSidlinskiy will tell you.. :P

Answer 3

R u sure about the statement?
because it is false.

Answer 4

say u set n=2 then
\[\large 9n-1=9\cdot2-1=18-1=17 \]
and 17 is not divisble by 8.