maths help

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Well the y-coordinate of E is clearly 7, since it likes on AB.

Then, since E lies on l as well, just sub that into the equation for l to find the x-coordinate.

thanks! mind went blank

for c) not sure what to do - i dont understand the wording

For the tangent to be parallel to that line they must have the same gradient. So, what's the gradient of the line? And can the gradient of the curve ever equal that?

for d) when i set it up like this: 1/2n (2x500 + (n-1) x 200) = 32000
shall i do the working out inside the bracket first so 1000 + 200n - 200. not sure if i should x both sides by 2 to make it 32000 x 2.
I understand how to answer these questions but i get the working out wrong

thanks again @ghostwalker

As long as you're following the rules of BODMAS, or whatever acronym you use, it doesn't matter. You can either multiply both sides by 2, or multiply the (1/2) by the bracket, so everything in the brackets is halved.

working out so far:

1/2n (2x500 + (n-1) x 200) = 32000

1/2n (1000 + 200n - 200) = 32000

1/2n ( 800 + 200n ) = 32000

not sure what to do now :/

As per my previous post. You could also expand the brackets.

In the end you will end up with a quadratic which you'll need to solve.

I have but i dont get a quadratic thats on the mark scheme thats my problem :/
i just get 400n + 100n^2 = 32000

So, what does the markscheme have - and please post the markscheme for the whole question.

I have but i dont get a quadratic thats on the mark scheme thats my problem :/
i just get 400n + 100n^2 = 32000

That is the same as the markscheme. You just need to divide evrything by 100 and rearrange.

thank u!!! from now on i will work out the bracket first its easier for me

i got (n+20)(n-16) on the markscheme it says 26 years
not sure how they got this