Find equation of this function (my answer is different from the books answer)

    • Thread Starter

    The graph of a parabola has a turning point at (-2, 4), write the equation of this function if it passes through point (2,8). The original equation is y = (x+2)^2 + 4

    I got: y = 0.25(x+2)^2+4
    The answer in my book is y=1/2(x+2)^2 +4

    PS: u gotta go use like: y = k(x+2)^2 + 4 to find the equation im guessing.

    Your function passes through the correct point, but the book's does not. However, it is unclear to me what your question even means. There are infinitely many parabolas with the features you have described, and you have not specified what relationship the 'original equation' has to any solution or why it has this relationship. The closest you have come is saying that you are guessing at some transformation, but you have not made it clear why you are guessing this.

    All things considered, it might be easier to answer if you post the wording of the original question.
    • Thread Starter

    Ah dont worry must be correct ;p thanks, because my book does have some mistakes and even my teacher said so that we should be careful as our workings will be correct however this book will show otherwise....


    It is correct ... there was a post before saying you were right so I did not post

    Your method is also correct ... use completing the square from the turning point ... multiplying the bracket by a constant since constant x 0 = 0 ... then putting in the second value

    I am not sure why Bobifier thinks there are infinite examples
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