simplifying a fraction with variables with negative exponent

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simplifying a fraction with variables with negative exponent

Postby brynnpet » Wed Nov 04, 2009 1:32 pm

This is my question:

in a problem like this...5 x squared divided by 10 x to the negative 5th power- how do i simplify this?

i think you say x squared minus x to the negative 5th = x to the 7th and the answer is 1/2 x to the 7th

my mom suggests that the rule does not apply for variables with negative integers- she thinks we must invert the x to the negative 5th and solve.

please give me some guidance on how to simplify this problem.

b- 6th grade student in florida
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Re: simplifying a fraction with variables with negative exponent

Postby Subhotosh Khan » Wed Nov 04, 2009 2:39 pm

brynnpet wrote:This is my question:

in a problem like this...5 x squared divided by 10 x to the negative 5th power- how do i simplify this?

i think you say x squared minus x to the negative 5th = x to the 7th and the answer is 1/2 x to the 7th <<<< You are correct

my mom suggests that the rule does not apply for variables with negative integers- she thinks we must invert the x to the negative 5th and solve.

please give me some guidance on how to simplify this problem.

b- 6th grade student in florida


In mathematics, you don't understand things. You just get used to them ......John von Neumann
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Re: simplifying a fraction with variables with negative exponent

Postby barson90 » Sun Nov 15, 2009 10:33 pm

I hope this won't confuse you, but another way to think about this is that if the ENTIRE denominator is raised to a negative power, then you can move it to the numerator and make the exponent positive. (Since we can factor out (1/2), we're left with x^(-5). So, the numerator becomes x^2 times x^5. When multiplying likes bases, in this case "x" , add the exponents. So, we have x^(2+5) = x^7
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