SOLUTION: Find all numbers for which each rational expression is undefined. If expression is defined for all real numbers, state so. 1) 8 _____ x^2+4 2) 7x-14

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Find all numbers for which each rational expression is undefined. If expression is defined for all real numbers, state so. 1) 8 _____ x^2+4 2) 7x-14      Log On


   

Question 674579: Find all numbers for which each rational expression is undefined. If expression is defined for all real numbers, state so.
1) 8
_____
x^2+4
2) 7x-14
_________
x^2-9x+20
3) x+5
_________
(x+7) (x-9)
Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
The expressions will be undefined where 0 is the denominator
...
1)
x%5E2+%2B+4+=+0
x%5E2+=+-4
sqrt%28x%5E2%29 = +/- sqrt%28-4%29
x = +/- sqrt%284%2A-1%29
x = +/- 2i
...
2)
x%5E2-9x%2B20+=+0
%28x-5%29%28x-4%29+=+0
x = 5 and 4
...
3)
(x-7)(x-9)=0
x = 7 and 9
.....................
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