Math HW due.. need help tonight bad.
Need to factor the following
(If I erase some of the problems, its because someone already did them. thanks)
2. 27x^3-64
3. 3x^3+x^2-12x-4
Math HW due.. need help tonight bad.
Need to factor the following
(If I erase some of the problems, its because someone already did them. thanks)
2. 27x^3-64
3. 3x^3+x^2-12x-4
$\displaystyle 27x^3 - 64$ is a difference of two cubes - consider it written as $\displaystyle (3x)^3 - 4^3$. Use the formula for difference of two cubes with $\displaystyle a=3x$ and $\displaystyle b=4$.
For the other problem, $\displaystyle 3x^3+x^2-12x-4$, out of the first two terms, factor $\displaystyle x^2$ and out of the last two terms factor out -4. This gives:
$\displaystyle x^2(3x+1)-4(3x+1)$. Now, both terms have a $\displaystyle (3x+1)$ in common, so factor that out, giving:
$\displaystyle (3x+1)(x^2-4)$. The last step for finishing this one is to factpr $\displaystyle x^2-4$, which is a difference of squares.
Hope this helps!