Thread: Stumbling! Help!!

Need help on how to approach these specific probs.

expand:
(2x^2-1)^2

Factor completely (factor common first)
y^4–6y^3+9y^2

factor/simplify lowest terms
9x^2-1 * x^2-1
__x-1 ___6x^2-2x

1 - 1
x_ x+2

Originally Posted by dude

expand:
(2x^2-1)^2

On this one just re-write it as and foil it out (use the distributive law). After foiling and collecting like terms you should get

expand:
(2x^2-1)^2

=(2x^2 -1)(2x^2 -1)
=4x^4-2x^2-2x^2+1
=4x^4 -4x^2 +1

Factor completely (factor common first)
y^4–6y^3+9y^2

=y^2(y^2 -6y +9)
=y^2(y-3)(y-3)
or y^2(y-3)^2


factor/simplify lowest terms
9x^2-1 * x^2-1
______ ______
x-1 6x^2-2x

=(9x^2-1)/(x-1)*(x^2-1)/(6x^2-2x)
=(3x-1)(3x+1)/(x-1)*((x+1)x-1)/2x(3x-1)
=(3x+1)(x+1)/2x




1/x-1/(x+2)
((x+2)-x)/(x(x+2))
2/(x^2+2x)

Originally Posted by dude

Factor completely (factor common first)
y^4–6y^3+9y^2

On this one try to find factors that each term have in common i.e. is there some way that you can re-write each term such that they each have a similar item?

for example I can re-write the original statement as
notice that if you multiply each of them back together it would make the same statement that we started with, and even more, notice that they each have a in common that we can factor out.

so if we factor out the we get Once again notice that if we multiply everything back out we will get the same as we started with.

Now we can factor what we have left to That last factoring is a little tricky, it is like undoing foiling.
so we should finish with

Hope this helps a little.