- #1
DS2C
Homework Statement
Completely factor:
$$5abc^4-80ab$$
Homework Equations
N/A
The Attempt at a Solution
$$5abc^4-80ab$$
$$5ab\left(c^4-16\right)$$
$$5ab\left(c^2+4\right)\left(c^2-4\right)$$
[/B]
The correct solution is ##5ab\left(c^2+4\right)\left(c+2\right)\left(c-2\right)##
I can see why it factored out the ##\left(c^2-4\right)## further, but why isn't it required to do so with the ##\left(c^2+4\right)## as well?