Question 69626
Let's check your answer by multiplying your factors together using the FOIL method (first terms, outside terms, inside terms, and last terms)

Your answer was:

{{{(2x+7)*(3x^2-1)}}}

Multiplying the first terms in each factor results in:

{{{2x * 3x^2 = +6x^3}}}
Multiplying the outside terms in each factor results in:
{{{2x*(-1) = -2x}}}
Multiplying the inside terms in each factor results in:
{{{7*3x^2 = +21x^2}}}
And finally, multiplying the last terms in each factor:
{{{7*(-1) = -7}}}

Algebraically adding all these terms in descending powers of x results in:

{{{6x^3 + 21x^2 - 2x - 7}}}

That is exactly the expression you started with.  So your answer is correct.  Excellent job. Keep up the good work!