SOLUTION: I am so confused on how to do this. Please Help! Find all numbers for which the rational expression is undefined: 9/5x+1

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: I am so confused on how to do this. Please Help! Find all numbers for which the rational expression is undefined: 9/5x+1       Log On


   

Question 557743: I am so confused on how to do this. Please Help!
Find all numbers for which the rational expression is undefined:
9/5x+1

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
For the expression to be undefined, it is necessary for the denominator be equal to zero.
9%2F%285x%2B1%29 Set the denominator equal to zero and solve for x.
5x%2B1+=+0 Subtract 1 from both sides.
5x+=+-1 Divide by 5.
x+=+-1%2F5
For x+=+-1%2F5 the expression is undefined.
9%2F%285x%2B1%29 Substitute x+=+-1%2F5
9%2F%285%28-1%2F5%29%2B1%29+=+9%2F%28-1%2B1%29=9%2F0 Undefined!