SOLUTION: find all nubers for wich the rate and expression is not defined. b-5/5b-20

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Question 187081: find all nubers for wich the rate and expression is not defined.
b-5/5b-20
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Remember, division by zero is NOT defined. So this means that ANY values that make the denominator of %28b-5%29%2F%285b-20%29 equal to zero will also make the expression undefined.


%28b-5%29%2F%285b-20%29 Start with the given expression.


5b-20=0 Set the denominator equal to zero.


5b=0%2B20 Add 20 to both sides.


5b=20 Combine like terms on the right side.


b=%2820%29%2F%285%29 Divide both sides by 5 to isolate b.


b=4 Reduce.


So when b=4, the expression 5b-20 is equal to zero.


In turn, when b=4 the denominator of %28b-5%29%2F%285b-20%29 is equal to zero.


So if b=4 this makes the expression %28b-5%29%2F%285b-20%29 undefined.