SOLUTION: twice the reciprocal of a number is nine more than five times the number. find the number

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Question 98600: twice the reciprocal of a number is nine more than five times the number. find the number
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
2*1/X=9+5X
2/X=9+5X NOW CROSS MULTIPLY
9X+5X^2=2
5X^2+9X-2=0
(5X-1)(X+2)=0
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FOIL f=first 5x*x=5x^2, o=outer-1*2=-2 i=inner-1*x=-x & l=last=2+5x=10x now combine all these terms you get 5x^2+10x-x-2 or 5x^2+9x-2
that's where the 9x went it became 10x-1x=9x.
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5X-1=0
5X=1
X=1/5 OR .2 ANSWER.
X+2=0
X-2 ANSWER.
PROOFS:
2*1/.2=9+5*.2
2*5=9+1
10=10
2*1/-2=9+5*-2
-1=9-10
-1=-1