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Math Help - help[

  1. #1
    Junior Member
    Joined
    Sep 2008
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    56

    help[

    ok so i got few questions so i was given a equation like this
    y= -1/4 | 2(x+1)|+9
    i identify that the parent function is y = |x| , but i totally forgot how to input the number.. as in when u plug in x what do u get as y. Does it always remain positive for an aboslute value.

    2.) so if u were given a equation like this y= -[ 1/2 (x+2)]^2+10 , the negative sign in the front, is represent as -1 = a , from the general formula. Or is it just a negative sign there, if so, do u not include the transformation of a in the graph?
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  2. #2
    MHF Contributor
    Joined
    Apr 2008
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    1,092
    1. The definition of the absolute value function is y = x if x is nonnegative, and y = -x if x is negative. So in order to evaluate |2(x+1)| = |2x + 2|, you put in the value for x, and then if 2x + 2 \geq 0, the value stays unchanged; otherwise, it becomes positive. For example, if x = 0, then 2x + 2 = 2(0) + 2 = 2, so |2x + 2| = |2| = 2. If x = -3, then 2x + 2 = 2(-3) + 2 = -4, and |2x + 2| = |-4| = 4.

    2. After you evaluate (.5(x+2))^2 = .25(x+2)^2, you see that a = -0.25. I'm not sure what you are asking here, though.
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