The actual problem is:
and I have to solve this by grouping.Thanks!
The actual problem is:
and I have to solve this by grouping.Thanks!
21x^{3} + 6x^{2} -28x - 8
It looks like you can pull a 7x out of the first and third terms, and a 2 from the second and fourth:
7x(3x^{2} - 4) + 2(3x^{2} - 4)
Then factor out what's in the parentheses to get (3x^{2} - 4)(7x + 2)^{ }