Homework Help

Which of the following is not a perfect square. A. x^2+4x+16 B. x^2+6x+9  C....

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christiano-cr7 | Salutatorian

Posted June 24, 2013 at 6:03 AM via web

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Which of the following is not a perfect square.

A. x^2+4x+16

B. x^2+6x+9 

C. 4x^2+4x+1

D. 1-2x+x^2

E. 9x^2-6x+1

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jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted June 24, 2013 at 6:14 AM (Answer #1)

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Let us consider the general form of a quadratic equation.

`ax^2+bx+c = 0`

When we have a perfect square that means we have the following combination.

`b^2-4ac = 0`

 

`A. x^2+4x+16`

`b^2-4ac = 16-4xx1xx16 = -48`

 

`B. x^2+6x+9`

`b^2-4ac = 6^2-4xx1xx9 = 0`

 

`C. 4x^2+4x+1`

`b^2-4ac = 16-4xx4xx1 = 0 `

 

`D. 1-2x+x^2`

`b^2-4ac = (-2)^2-4xx1xx1 = 0 `

 

`E. 9x^2-6x+1`

`b^2-4ac = (-6)^2-4xx9xx1 = 0`

 

So the answer is A.

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