la_nena26

07-11-2006, 05:00 PM

25x^2 - 64 = 0

please help me! :cry:

please help me! :cry:

View Full Version : I am lost: 25x^2 - 64 = 0

la_nena26

07-11-2006, 05:00 PM

25x^2 - 64 = 0

please help me! :cry:

please help me! :cry:

tkhunny

07-11-2006, 05:02 PM

You simply MUST learn to recognize a "Difference of Squares".

25x^2 - 64 = (5x+8)(5x-8)

If all else fails, you can ALWAYS use the quadratic formula.

25x^2 + 0x - 64 ==> a = 25, b = 0, c = 64

25x^2 - 64 = (5x+8)(5x-8)

If all else fails, you can ALWAYS use the quadratic formula.

25x^2 + 0x - 64 ==> a = 25, b = 0, c = 64

la_nena26

07-11-2006, 05:17 PM

You simply MUST learn to recognize a "Difference of Squares".

25x^2 - 64 = (5x+8)(5x-8)

If all else fails, you can ALWAYS use the quadratic formula.

25x^2 + 0x - 64 ==> a = 25, b = 0, c = 64

is it the same if you are adding?

25x^2 - 64 = (5x+8)(5x-8)

If all else fails, you can ALWAYS use the quadratic formula.

25x^2 + 0x - 64 ==> a = 25, b = 0, c = 64

is it the same if you are adding?

tkhunny

07-11-2006, 05:31 PM

is it the same if you are adding?No. That doesn't work. Both sum and difference of CUBES can be factored.

la_nena26

07-11-2006, 06:11 PM

so if i got 16n^2+18n=0

i know i have to find the square of 16 which is 4

(4n+ )(4n+ ) what do i do next with the 18?

i know i have to find the square of 16 which is 4

(4n+ )(4n+ ) what do i do next with the 18?

stapel

07-11-2006, 06:46 PM

so if i got 16n^2+18n=0

In future, please post new questions as new threads, not as replies to old questions where they may be overlooked (or answered incorrectly). Thank you.

To solve a quadratic by factoring, first factor whatever is common to all of the terms. In the case of 16n<sup>2</sup> + 18n, there is a 2n common to both terms.

Eliz.

In future, please post new questions as new threads, not as replies to old questions where they may be overlooked (or answered incorrectly). Thank you.

To solve a quadratic by factoring, first factor whatever is common to all of the terms. In the case of 16n<sup>2</sup> + 18n, there is a 2n common to both terms.

Eliz.

jonboy

07-11-2006, 07:32 PM

We have: \L 16n^2+18n=0

As stapel said we have a common term of \L 2n

So: \L 2n(8n+9)=0

As stapel said we have a common term of \L 2n

So: \L 2n(8n+9)=0

la_nena26

07-11-2006, 08:37 PM

Thanks everybody! :D

Denis

07-12-2006, 12:05 AM

25x^2 - 64 = 0

Worth a shot at isolating x^2:

25x^2 = 64

x^2 = 64 / 25

x = +-sqrt(64 / 25)

x = +- 8/5

Worth a shot at isolating x^2:

25x^2 = 64

x^2 = 64 / 25

x = +-sqrt(64 / 25)

x = +- 8/5

Powered by vBulletin® Version 4.2.2 Copyright © 2014 vBulletin Solutions, Inc. All rights reserved.