Question #bf489

Observe that:
Difference in each step for advertising is +2
Difference in each step for revenue is +4

Let the advertising signature be `i`
Let the ith advertising signature be `a_i`

`color(blue)("Consider the number structure")`

`a_0->2`
`a_2->6`
`a_4->10`
`a_6->14`
`a_8->18`
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We need to relate `i` to revenue. `a_0->(0-2)+4=2`

`color(red)(a_0->-2+4=2)`
`color(red)(a_2->-2+4+4=6)`
`color(red)(a_4->-2+4+4+4=10)`
`color(red)(a_6->-2+4+4+4+4=14)`
`color(red)(a_8->-2+4+4+4+4+4=18)`
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Lets try something:

`color(red)(a_0->-2+4=2)`
`color(green)(a_1->-2+4+2=4)`
`color(red)(a_2->-2+4+2+2=6)`
`color(green)(a_2->-2+4+2+2+2=8)`
`color(red)(a_4->-2+4+2+2+2+2=10)`
`color(green)(a_5->-2+4+2+2+2+2+2=12)`
`color(red)(a_6->-2+4+2+2+2+2+2+2=14 )`
`color(green)(a_7->-2+4+2+2+2+2+2+2+2=16)`
`color(red)(a_8->-2+4+2+2+2+2+2+2+2+2=18 )`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is the same as:
`a_0->2=2`
`a_1->2+2=4`
`a_2->2+2+2=6`
`a_3->2+2+2+2=8`
`a_4->2+2+2+2+2=10`
`a_5->2+2+2+2+2+2=12`
`a_6->2+2+2+2+2+2+2=14`
`a_7->2+2+2+2+2+2+2+2=16`
`a_8->2+2+2+2+2+2+2+2+2=18`

so any `a_i=2(i+1) =2i+2`

As this is linear we use the standardised format `y=mx+c`

Set `i=x` giving: `y=2x+2`

I will let you draw the graph