# How do I find the value of n?

## Homework Statement

How do I find the value of n?

## Homework Equations

I know that when it crosses x axis y = 0
X3 - X2 - 20 =0
But don't know how to solve it from here

## The Attempt at a Solution

The marking scheme says 3.0 or 3.1
I couldn't get the answer even by substituting
I know I'm doing something stupid

#### Attachments

• 15343398957956967716792335949451.jpg
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phinds
Gold Member
Have you googled "how to solve a cubic equation" ?

The answer was there in the previous part
Thank you

Mark44
Mentor
@lioric, what's the complete problem? In the image you posted, there is no "n".

phinds
Gold Member
@lioric, what's the complete problem? In the image you posted, there is no "n".
Look closer.

Squint like Clint

#### Attachments

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Last edited:
berkeman
Mark44
Mentor
I was already squinting, looking at that unclear and incomplete image. By "there is no n" I meant that the equation doesn't involve n.

Ray Vickson
Homework Helper
Dearly Missed
Look closer.

View attachment 229330
Squint like Clint
When I looked at it the first time (on my phone) there was no n. When I looked at it later (on my laptop) there was, magically, an n.

mathwonk