Question 1159538
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<pre>

Had the binomial (7+3x) been a factor of the polynomial  p(x) = {{{3x^3+7x}}}. then 
the number  x= -{{{7/3}}}  would be the zero of the polynomial p(x).



But you can easily check on your own, that   p(-7/3)  is not equal to zero.



This contradiction  <U>PROVES</U>  that   7+3x  <U>IS NOT</U>  the factor of 3x^3 + 7x.
</pre>

The proof is completed.