- #1

- 37

- 0

## \forall y \in (x | x \in \mathbb Z , x \geq 1), 5y^2 + 5y + 1 ##

I think it's true, but I can't really even get started to prove it

I really suck at these and need help please, thank you!

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- Thread starter zoxee
- Start date

- #1

- 37

- 0

## \forall y \in (x | x \in \mathbb Z , x \geq 1), 5y^2 + 5y + 1 ##

I think it's true, but I can't really even get started to prove it

I really suck at these and need help please, thank you!

- #2

mfb

Mentor

- 35,339

- 11,648

It is like "prove that this is true or false: 5".

I guess there is "is prime" missing. Did you test some numbers to check it? Don't just check small numbers, consider larger numbers as well.

Big hint:

- #3

.Scott

Homework Helper

- 2,678

- 985

For y = 1 To 100

z = 5*y*y + 5*y + 1

if (z mod 11)=0 then MsgBox("f(" & y & ") is divisible by 11.")

if (z mod 19)=0 then MsgBox("f(" & y & ") is divisible by 19.")

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- #4

HallsofIvy

Science Advisor

Homework Helper

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Where did "divisible by 5" and "divisible by 11" come from?

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