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Quadratic Formula

Directions: Using the digits 1 to 9, at most one time each for a, b, and c, find the result with the greatest and least value:

Hint

What will the exponent do?
What will the radical do?

Answer

Assuming the solution can be negative, the greatest value would occur when a=2, b=9, and c=1 (solution = -0.11). The least value, found by Robert Hays, would occur when a=1, b=9, c=2 (solution = -8.77)

Source: Dane Ehlert

Tags A-SSE.1 Dane Ehlert DOK 3: Strategic Thinking

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4 comments

Robert Hays
August 12, 2015 at 2:48 pm

I agree with the largest value a=2, b=9, c=1 ( solution = 0.11 )

The smallest value I found was a=1, b=9, c=2 ( solution = -8.77 )

Reply
- Robert Kaplinsky
  December 17, 2015 at 1:13 pm
  
  Thanks Robert! The answer has been updated.
  
  Reply
- MRO
  April 24, 2017 at 10:08 am
  
  a=1, b=9, c= 1 gives -0.11251…
  a=2, b=9, c=1 gives -0.113999…
  
  Reply
  - Robert Kaplinsky
    July 2, 2018 at 1:55 pm
    
    Thanks MRO. The problem with a=1, b=9, c= 1 is that you cannot repeat a digit.
    
    Reply