To factor the expression x3 + 4x2 + 7x + 28 by grouping, we can break it into two groups.
First, we group the first two terms and the last two terms:
(x3 + 4x2) + (7x + 28)
Now, we can factor out the greatest common factor (GCF) from each group:
From the first group, x2 can be factored out:
1. x2(x + 4)
From the second group, 7 can be factored out:
2. 7(x + 4)
Now we combine these factored groups:
x2(x + 4) + 7(x + 4)
Notice that (x + 4) is now a common factor:
We can factor it out:
(x + 4)(x2 + 7)
Thus, the resulting expression after factoring by grouping is:
(x + 4)(x2 + 7)