#Help me with this grade 9 question pls

56 messages · Page 1 of 1 (latest)

fervent island
#

With all of n that n is not divisiable by 2 prove that 3^2n+1 is divisable by 20

worldly pumiceBOT
fervent island
#

<@&286206848099549185>

fervent island
#

<@&286206848099549185>

wintry monolith
#

3^1 = ..3
3^2 = ..9
3^3 = ..7
3^4 = ..1
3^5 = ..3

#

and then work your way to prove that the numerator is divisible by both 5 and 4

fervent island
#

it is 3^2n+1 -7

#

<@&286206848099549185>

wintry monolith
#

exactly

#

duh?

fervent island
#

so how tf that thing can help me

wintry monolith
#

this is literally all the hints lol

fervent island
#

that was i need if you can solve it i can solve it also

wintry monolith
#

To be clear is it 3^(2n+1)/20 or 3^(2n)+1/20

#

and yes it is solvable

fervent island
wintry monolith
#

so which one is it

fervent island
#

3^2n+1-7

#

with n undivisable by 2

#

oh

#

i think i know how to solve it

wintry monolith
#

2n = 2 * odd = even
2n + 1 = odd

#

3^something exclusively odd

compact bay
fervent island
#

I mean (3^(2n+1))-7

hushed sage
fervent island
compact bay
#

that's not true though

#

,w 3^(2 * 2 + 1) - 7

strange capeBOT
compact bay
#

^ not divisible by 20

fervent island
#

it gonna be 3^(2(2k+1)+1)-7= 3^(4k+3)-7 = 81^k*27-7

fervent island
#

,w 3^(2 * 1 + 1) - 7

strange capeBOT
fervent island
#

see

#

,w 3^(2 * 3 + 1) - 7

strange capeBOT
compact bay
#

ah

fervent island
#

still divisable

compact bay
fervent island
#

you mean mod(81,20)?

compact bay
#

exactly

#

consider it mod 20

fervent island
#

1^k*27-7

#

oh

#

it solved

#

lmao

compact bay
#

yep

fervent island
#

thanks

compact bay
#

np

fervent island
#

lol

fervent island