<PRE><B>Question 56159</B>
1+1/x=90/x2 
In words, one plus one over x equals 90 over x squared
:
1 + {{{1/x = 90/x^2}}}
:
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

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