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andypanda
Nov 29, 2006, 04:20 PM
I have a few questions concerning functions...
1) X^3+64
2) 54p^3-16q^3
3) 2x^2-5x=3
4) 2x^2-8x=0
:confused: :confused:

worthbeads
Nov 29, 2006, 04:43 PM
What exactly are you having trouble with?

galactus
Nov 30, 2006, 07:59 AM
I have a few questions concerning functions...
1) X^3+64
2) 54p^3-16q^3
3) 2x^2-5x=3
4) 2x^2-8x=0
:confused: :confused:
It appears you want to factor.

The first one is the sum of 2 cubes... Easy.

3 and 4 are completing the square.

The 2nd one is the difference of 2 cubes, but a little trickier. I'll do it and you try the others.

54p^3-16q^3

Factor out 2:

2(27p^3-8q^3)

Make into a difference of cibes inside the parentheses:

2((3p)^3-(2q)^3)

Now, let x=3p and y=2q:

2(x^3-y^3)

Difference of cubes formula:

2(x-y)(x^2+xy+y^2)

Resub:

2(3p-2q)((3p)^2+(3p)(2q)+(2q)^2)

2(3p-2q)(9p^2+6pq+4q^2)

Does that help?