Question 1209569
.
1 + 4 + 7 + 10 + ... + x = 287
find x
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It is an anti-mathematical way to present a problem.


It makes me feel sick.


As well as any other person,  who has a  Math education and feeling of harmony . . . 



Normal and standard  " human "  way  (= right way)  to formulate this problem mathematically is  THIS


<pre>
    The sum of the first n terms of an arithmetic progression
    with the first term 1 and the common difference 3 is 287.
    Find the number of terms "n" and the value of the n-th term.
</pre>


How the problem is presented in your post is &nbsp;{{{highlight(highlight(GIBBERISH))}}}.


It reminds me of how the witch doctors stir the potion in cups, 
in &nbsp;700 &nbsp;years old tales.