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Apply the quadratic formula to x^2+11x-48

 Nov 26, 2015

Best Answer 

 #2
avatar+118612 
+5

YOU CANNOT APPLY THE QUADRATIC FORMULA TO THAT BECAUSE IT IS NOT AN EQUATION.

IT MUST = 0   !!

 Nov 26, 2015
 #1
avatar
+5

I can't DRAW the Quadratic Formula, but it is

 

(   -b +- sqrt( b^2 -4ac) )  /  2a

 

In this equation   a = 1   b=11  c= -48   

Substituting:

 (-11 +- sqrt(121 - (-192)) / 2  =  -11 +- sqrt313 =  (-11 +-17.69) / 2 = -28.69/2    and    6.69/2       or   -14.35    and 3.35

 

As a check, you can substitute these values BACK into the ORIGINAL equation to see if they are true....

 Nov 26, 2015
 #2
avatar+118612 
+5
Best Answer

YOU CANNOT APPLY THE QUADRATIC FORMULA TO THAT BECAUSE IT IS NOT AN EQUATION.

IT MUST = 0   !!

Melody Nov 26, 2015
 #3
avatar
+5

I realize that Melody, but like so many other posts on here, you have to make some assumptions about what is being asked...Often I will write my assumptions in my posted answers, but this time I made the assumption that =0 was just left off in the question and solved it with that....

 Nov 26, 2015
 #4
avatar+118612 
0

 

Hi guest,      smiley

I appreciate that you offered an answer, I want everyone to participate and I hope that you are not offended by my involvement.  I also hope that you and the asker both learn someting positive from my input here.

 

In this case it was a necessary for you to state your assumption.

You see, this student, and many others, do not understand that they are solving an equation that must be equal to zero.

SO the most important thing was to teach the student why their question made no sense.

 

When answerers make assumptions they must state it.  

They may do this just by rewriting the question properly (as they assume it to be) 

OR they may make a song and dance about it like I have here.

BUT either way, the questioner must be told what question you are answering.   smiley

 Nov 27, 2015
edited by Melody  Nov 27, 2015

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