3/n-5 - 1/5-n Need help solving this problem....need to find common demoninator first...thanks
2007-01-12 13:50:13 · 6 answers · asked by gail 1 in Science & Mathematics ➔ Mathematics
OK...5-n is equal to (n-5)*(-1), therefore your problem is:
3/n-5 + 1/n-5. Obviously this is 4/n-5.
The long way:
3/n-5- 1/5-n= (15-3n-n+5)/(n-5)(5-n)
=(20-4n)/(n-5)(5-n)
=4(5-n)/(n-5)(5-n)
=4/n-5
2007-01-12 14:02:20 · answer #1 · answered by samuelll 2 · 0⤊ 0⤋
Note: 5 - n = - (- 5 + n) = - (n - 5)
3/(n-5) - 1/(5-n)
= 3 / (n - 5) - 1 / [ -(n - 5)]
= 3 / (n - 5) + 1 / (n - 5)
=(3 + 1) / (n - 5)
= 4 / (n - 5)
2007-01-12 22:00:31 · answer #2 · answered by Sheen 4 · 0⤊ 0⤋
You can simplifty the above expression to another level:
(-4n+20/(n-5)-(n-5) = -4(n-5)/-1(n-5)^2 = 4/n-5.
2007-01-12 22:06:11 · answer #3 · answered by Dr Dave P 7 · 0⤊ 0⤋
(3/(n - 5)) - (1/(5 - n))
(3/(n - 5)) - (1/(-n + 5))
(3/(n - 5)) - (1/(-(n - 5)))
(3/(n - 5)) + (1/(n - 5))
(3 + 1)/(n - 5)
4/(n - 5)
2007-01-12 23:12:19 · answer #4 · answered by Sherman81 6 · 0⤊ 0⤋
The common denominator is (n-5)(5-n).
So, we have in the numerator 3(5-n) - 1(n-5) = 15 - 3n - n + 5 = -4n + 20
So the final answer is (-4n+20)/[(n-5)(5-n)]
2007-01-12 21:53:27 · answer #5 · answered by JasonM 7 · 0⤊ 0⤋
the answer is 2/1.
1/5-n can be switched arount to n+5....
so 1/n+5
so n-5 - n+5... you add... which simply equals 1.
3-1 = 2.
so 2/1
2007-01-12 23:52:38 · answer #6 · answered by locke32080 1 · 0⤊ 0⤋