Online Course Discussion Forum

Math Challenge IIA Algebra

 
 
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Math Challenge IIA Algebra
by Yizhou Zhang - Sunday, 18 August 2019, 11:45 AM
 
3.18 Quick Response Question


Can you tell me why the online answer says -2 divided by 1/2=4?

Is it suppose to be -4?

 
Picture of David Reynoso
Re: Math Challenge IIA Algebra
by David Reynoso - Monday, 19 August 2019, 3:04 PM
 

This seems to be a typo, since the sum of the roots $r + s = 2$. So, the solution should say $$\dfrac{1}{r} + \dfrac{1}{s} = \dfrac{r + s}{rs} = \dfrac{2}{\frac{1}{2}} = 4.$$

Thanks for pointing this out!