x/x+9 - 9/x-9 = x^2+81/x^2-81.......thank you
2007-08-20 18:26:23 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Do your own homework!!!
2007-08-20 18:33:42 · answer #1 · answered by Gab&Thomas 5 · 3⤊ 4⤋
Since (x+9)(x-9)= x^2 - 81 is the difference of squares.
Use it to multiply the whole equation and get:
x(x-9) - 9(x+9) = x^2 + 81
x^2 -9x -9x -81 = x^2 + 81
-18x = 162
x= - 9
2007-08-20 18:48:57 · answer #2 · answered by 037 G 6 · 0⤊ 2⤋
Solve for x.
I think you mean
x/(x + 9) - 9/(x - 9) = (x² + 81)/(x² - 81)
{x(x - 9) - 9(x + 9)} / [(x + 9)(x - 9)] = (x² + 81)/(x² - 81)
{x² - 9x - 9x - 81} / (x² - 81) = (x² + 81)/(x² - 81)
x² - 18x - 81 = x² + 81
-18x = 162
x = -9
2007-08-20 19:07:28 · answer #3 · answered by Northstar 7 · 3⤊ 1⤋
x / (x + 9) - 9 / (x - 9) = (x² + 81) / (x - 9)(x + 9)
x(x - 9) - 9(x + 9) = x² + 81
x² - 9x - 9x - 81 = x² + 81
- 18x = 162
x = - 162 / 18 = - 54 / 6 = - 9
x = - 9
2007-08-20 19:42:33 · answer #4 · answered by Como 7 · 3⤊ 1⤋
it's just a matter of combining similar terms...
x/(x+9) - 9/(x-9) = (x^2 + 81)/(x^2 -81)
multiply the whole equation with x^2- 81 (the least common denominator)
it will become...
x (x-9) - 9 (x+9) = x^2 + 81
x^2 - 9x - 9x - 81 = x^2 + 81
combine like terms...
18x = -162
x = -9
hope it helps...
2007-08-20 19:15:33 · answer #5 · answered by >bLueeyes< 2 · 0⤊ 4⤋
x / (x + 9) - 9 / (x - 9) = (x^2 + 81) / (x^2 - 81)
x(x - 9) - 9(x + 9) = x^2 + 81
x^2 - 9x - 9x - 81 = x^2 + 81
- 18x = 162
x = 162/18 = 9
2007-08-20 18:43:25 · answer #6 · answered by Helmut 7 · 0⤊ 3⤋
Your homework is your problem for not paying attention in class.
Even I can work that one out and I never did that much algebra at school because they thought I was thick or stupid.
Look at it and from the point of x/x+9 which to most math people will pop up like one of those kiddie books.
2007-08-20 18:38:04 · answer #7 · answered by cheek_of_it_all 5 · 1⤊ 4⤋
add 9/x-9 to the right side
and multiply both sides by x+9
2007-08-20 18:40:56 · answer #8 · answered by xenon 5 · 0⤊ 3⤋
82 x^2 - 18x -162 = x^4
2007-08-20 18:36:52 · answer #9 · answered by sv1973 2 · 0⤊ 4⤋