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# Exponential graph GCSE past papers question watch

1. I'm having some trouble with the question in the picture. I used some trial and error to find an answer, but I'm sure there must be another way of doing it. Any ideas? Thanks.
2. You have two points, let's use the first one: and .
3. (Original post by Zacken)
You have two points, let's use the first one: and .
Thanks! I've worked it out now using that to form the equation 320/q^3=5 and solving it.
4. (Original post by Lelanor)
Thanks! I've worked it out now using that to form the equation 320/q^3=5.
Do you mean ?
5. (Original post by Zacken)
Do you mean ?
Well, I did this:
320/q^3 = 5
320 = 5q^3
q^3 = 64
q = 4
But that's pretty much the same thing.
6. (Original post by Lelanor)
Well, I did this:
320/q^3 = 5
320 = 5q^3
q^3 = 64
q = 4
But that's pretty much the same thing.
Fair enough. You cool with the method?
7. (Original post by Zacken)
Fair enough. You cool with the method?
Yep, your first post nudged me in the right direction. I realised I'd have to form some kind of equation(s) but I just couldn't work out what, so thanks
8. (Original post by Lelanor)
Yep, your first post nudged me in the right direction. I realised I'd have to form some kind of equation(s) but I just couldn't work out what, so thanks

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