2

When I complete the square, and I get this for example:

$$-(x+3)^2 - 13$$

What would $A, B$ and $C$ be? For example, when using $C - B^2 / 4A$

Thanks!

3SAT
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Alex
  • 179
  • 1
    Your notation is not entirely clear. Are the capital $A,$ $B$ and $C$ supposed to mean something different from the lowercase letters? Do you simply want the second-, first- and zero-th degree coefficients of a quadratic polynomial? – Justpassingby Feb 22 '16 at 07:39
  • @Justpassingby yes :) Sorry, I wrote them in capitals! – Alex Feb 22 '16 at 07:42

3 Answers3

1

$$-(x+3)^2 - 13=\color{red}{-1}x\color{blue}{-6}x\color{green}{-22}$$
so $A=\color{red}{-1}, B=\color{blue}{-6},C=\color{green}{-22}$ this is what you're looking for?

3SAT
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1

$-(x+3)^2-13=-(x^2+6x+9)-13=-x^2-6x-22=\color\red{(-1)}x^2+\color\red{(-6)}x+\color\red{(-22)}$

Hence:

  • $a=-1$
  • $b=-6$
  • $c=-22$
barak manos
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0

Let $(x+a)^2+b=Ax^2+Bx+C$

Then $A=1, B=2a, C=a^2+b$.

In your case we have to watch the signs:

Let $-(x+a)^2-b=Ax^2+Bx+C$

Then $A=-1, B=-2a, C=-a^2-b$.

$A=-1, B=-6, C=-22$

JMP
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