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 June 17th, 2012, 11:43 PM #1 Senior Member   Joined: Apr 2008 Posts: 193 Thanks: 3 Is the answer key wrong? This is the question. Consider an absolute value equation in the form f(x) = a + I x + b I. Its graph has the vertex at (-1,-2) and the x-intercepts at (-3,0) and (1,0). Find the values of a and b. This is actually a very easy question. My answer is a=-2 and b=-1. But, the answer key says a=-2 and b=1. I don't know if my answer or the answer key is wrong. Could someone please explain? Thanks.
 June 17th, 2012, 11:54 PM #2 Senior Member     Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,204 Thanks: 511 Math Focus: Calculus/ODEs Re: Is the answer key wrong? For the function: $f(x)=|x-h|+k$ The vertex is at $(h,k)$ Putting the given function into this form, we have: $f(x)=|x-(-b)|+a$ Hence the vertex is: $(-b,a)=(-1,-2)\:\therefore\:a=-2,\,b=1$
 June 18th, 2012, 03:55 AM #3 Global Moderator     Joined: Oct 2008 From: London, Ontario, Canada - The Forest City Posts: 7,879 Thanks: 1087 Math Focus: Elementary mathematics and beyond Re: Is the answer key wrong? | -3 + b | + a = 0 [1] | 1 + b | + a = 0 [2] [1] - [2]: | -3 + b | - | 1 + b | = 0 | -3 + b | = | 1 + b | | -3 + b |² = | 1 + b |² b² - 6b + 9 = b² + 2b + 1 -6b + 9 = 2b + 1 8b = 8 b = 1.

### 12a 8b = 12075 algebra

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