Having a Derp moment.

Alright, so I'm doing some Intermediate algebra, specifically simplifying factors, and I completely forgot if it's allowed to cross out denominators that are next to each other.

i.e.

3x(x)                            x
_____              ---     ________
(3x+4)(3x-4)           3x+4

Would it be possible to cross out the 3x+4's?

>>1
Are you asking if \textstyle\frac22-\frac12=2-1?

Cross out no, factor out yes.

sure...shit if I know though.

>>3
Do you know what \frac22-\frac12 means...?

>>1
No, you want to compress the two fractions into a single fraction.  You first need to make both denominators be (3x+4)(3x-4), so that means you need to multiply the second fraction by (3x-4) on the top and also again on the bottom (equivalent to just multiplying by 1, so nothing is really changed).

(3x^2)/((3x+4)(3x-4)) - x/(3x+4)

(3x^2)/((3x+4)(3x-4)) - x(3x-4)/((3x+4)(3x-4))

(3x^2)/((3x+4)(3x-4)) - (3x^2 - 4x)/((3x+4)(3x-4))

(4x)/((3x+4)(3x-4))

(4x)/(9x^2 - 16)

>>1
derp
Back to the imageboards, please