Answer:
[tex]7x(x+2y-3yz)[/tex]
Step-by-step explanation:
First we find the greatest common factor of the coefficients, 7, 14 and 21.
The greatest common factor is 7.
Factor 7 out and divide the terms by 7:
[tex]7x^2+14xy-21xyz=7(x^2+2xy-3xyz)[/tex]
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Next, we find the greatest common factor of [tex]x^2,xy[/tex] and [tex]xyz[/tex].
The greatest common factor is x.
Factor x out and divide the terms by x:
[tex]7(x^2+2xy-3xyz)=7x(x+2y-3yz)[/tex]