SOLUTION: Can you please help me solve this question? 1+1/x=90/x2 In words, one plus one over x equals 90 over x squared.

Algebra ->  Exponents-negative-and-fractional -> SOLUTION: Can you please help me solve this question? 1+1/x=90/x2 In words, one plus one over x equals 90 over x squared.      Log On


   



Question 56159: Can you please help me solve this question?
1+1/x=90/x2
In words, one plus one over x equals 90 over x squared.

Found 2 solutions by ankor@dixie-net.com, stanbon:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
1+1/x=90/x2
In words, one plus one over x equals 90 over x squared
:
1 + 1%2Fx+=+90%2Fx%5E2
:
Mult equation by x^2 and you have:
x^2 + 1x = 90
:
x^2 + x - 90 = 0; our old friend the quadratic equation
:
Easily factored:
(x + 10)(x - 9) = 0
:
x = -10 and x = +9
:
:
Check both solutions in original equation:
x = -10:
1 + (1/-10) = 90/(-10)^2
1 - (1/10) = 90/100
;
x = +9
1 + 1/9 = 90/9^2
1 + 1/9 = 90/81
10/9 = 10/9
:
both solutions check out

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
1+1/x=90/x2
Multiply thru by x^2 to get:
x^2+x=90
x^2+x-90=0
(x+10)(x-9)=0
x=-10 or x=9
Cheers,
Stan H.