It's difficult for me to understand how to work with rational expressions. So along with this-- Could someone explain the basic concept also?
Please answer by 10:00 PM Pacific! Thanks in advance. :)
2007-04-23 13:18:59 · 4 answers · asked by DTSL 2 in Science & Mathematics ➔ Mathematics
Hello. It is 1:21 am GMT here in UK. Have no idea when 10:00 PM Pacific is, so I'll answer straight away :-)
8a/(a² - 16) · (a+4)/4 =
multiply tops, multiply bottoms
= 8a·(a+4) / (a² - 16)·4 = ...
Now factorize a² - 16 = (a² - 4²) = (a - 4)(a + 4)
{using the formula (a² - b²) = (a - b)(a + b)}
...= 8a·(a+4) / (a - 4)(a + 4)·4
now the factor (a+4) on the top cancels with the factor (a+4) on the bottom
...= 8a / (a - 4)·4
... and finally divide top and bottom by 4
...= 2a / (a - 4)
Hope this helps!
2007-04-23 13:21:50 · answer #1 · answered by M 6 · 5⤊ 1⤋
First, let's figure out that a^2 - 16 = (a+4)*(a-4)
So, the multiplication is equal to 8a/((a+4)*(a-4))*(a+4)/4
= 8a/((a-4)*4)) = 2a/(a-4)
2007-04-23 21:05:45 · answer #2 · answered by elmo s 1 · 0⤊ 0⤋
8a/a^2-16 x a+4/4
8a/(a-4)(a+4) x a+4/4=
cancel out the 2 a+4
cancel out 8a tomake it 2a and 4 becomes1
2a/a-4
2007-04-23 20:30:56 · answer #3 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋
factorize a^2 - 16 = (a+4)*(a-4)
So the (a+4) cancels with the other a+4
You get 8a / [(a+4)*(a-4)] * (a+4) / 4
= 2a / (a-4)
How's it going on the west coast? Do you do a lot of scuba diving down there?
2007-04-23 20:23:04 · answer #4 · answered by Dr D 7 · 0⤊ 3⤋