Answer:
4n^2(7n - 10)(n + 2)
Step-by-step explanation:
The first step in factoring is to try to factor out a common factor.
28n^4 + 16n^3 - 80n^2 =
The GCF of all terms is 4n^2, so we factor out 4n^2.
= 4n^2(7n^2 + 4n - 20)
Now we need to factor the quadratic trinomial.
We can use the ac method.
Multiply ac = 7 * (-20) = -140
We need two factors of -140 that multiply to 4.
The factors are -10 and 14.
We rewrite the middle term, 4n as 14n - 10n.
= 4n^2(7n^2 + 14n - 10n - 20)
Now we factor by parts.
= 4n^2[7n(n + 2) -10(n + 2)]
= 4n^2(7n - 10)(n + 2)
