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# Graphs and functions help watch

1. Hi there,

Hope someone can help me with this I don't know how to do it and have been struggling for a while. I know you use a point and sub it into the equation, and then randomly i but b as 1 to get A is 3, and it's the right answer but I honestly just decided to use 1 because I used one point to sub in the y and x value then used the other point as a and b ( so used -1,1 for x and you then used the point 1,9 but to find a I made b 1). So can some explain how to do them so I'm not guessing my way through it or just making it up, the help would be much appreciate! I have a test next week so need to know it but only see my maths teacher once a week and can't ask him.
Thanks
2. (Original post by bananagrimshaw)
...
Begin by constructing the two simultaneous equations by plugging in the shown coordinates:

Then divide one by the other and proceed from there.
3. (Original post by RDKGames)
Begin by constructing the two simultaneous equations by plugging in the shown coordinates:

Then divide one by the other and proceed from there.
Thanks for taking the time to answer my question, but could you show me what you mean? I'm sorry to be a pain it's just when I done it I never got a=3 and b=1, i can get a=3 but not b=1 when I have done it. It would be much appreciated thank you
4. (Original post by bananagrimshaw)
Thanks for taking the time to answer my question, but could you show me what you mean? I'm sorry to be a pain it's just when I done it I never got a=3 and b=1, i can get a=3 but not b=1 when I have done it. It would be much appreciated thank you
Well if you get a=3 then you're almost done. Simply plug it into one of the equations and solve for b.

and diving both sides by 3 gives you so b must be equal to 1.
5. (Original post by RDKGames)
Well if you get a=3 then you're almost done. Simply plug it into one of the equations and solve for b.

and diving both sides by 3 gives you so b must be equal to 1.
Thank you very much! I'm a visual learner so had to see it done thanks again you've really help me
6. (Original post by bananagrimshaw)
Thank you very much! I'm a visual learner so had to see it done thanks again you've really help me
No worries.

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