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Math Help - please help

  1. #1
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    please help

    how do i factor b2 (squared) - 18b -144
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  2. #2
    Behold, the power of SARDINES!
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    Quote Originally Posted by mathdummy232 View Post
    how do i factor b2 (squared) - 18b -144
    We need to find factors of -144 that add up to -18

    lets check a few

    -12 \cdot 12=-144 \\\ -12+12=0 nope

    -6 \cdot 24=-144 \\\ -6+24=18

    This is the right number but the wrong sign so we switch the minus sign

    6 \cdot (-24)=-144 \\\ 6+(-24)=-18

    so Now if factors into

    (b+6)(b-24)
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  3. #3
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    Thanks so much

    would you know how to do this equation too? It says subtract ( -2x+2) - (x2 (square) +x-3)
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  4. #4
    Behold, the power of SARDINES!
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    Quote Originally Posted by mathdummy232 View Post
    would you know how to do this equation too? It says subtract ( -2x+2) - (x2 (square) +x-3)
    (-2x+2)-(x^2+x-3)

    First we distribute the minus sign(or - is the same as -1), then collect the like terms

    -2x+2-x^2-x+3=-x^2-3x+5

    Good luck.

    P.S. When you have an unrealated question it is okay to start a new thread
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  5. #5
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by mathdummy232 View Post
    would you know how to do this equation too? It says subtract ( -2x+2) - (x2 (square) +x-3)
    New questions need to go in new threads.

    -Dan
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  6. #6
    Math Engineering Student
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    \begin{aligned}<br />
   b^{2}-18b-144&=\left( b^{2}-18b+81 \right)-144-81 \\ <br />
 & =(b-9)^{2}-225=(b-9)^{2}-15^{2} \\ <br />
 & =(b-9+15)(b-9-15) \\ <br />
 & =(b+6)(b-24).<br />
\end{aligned}
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