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Given $f (x) = 8 x - 9$ $f(x) =8x - 9$ how do you find f(-2)?

1 Answer

Feb 17, 2016

$f (- 2) = - 25$ $f(-2)=-25$

Explanation:

If $f (x) = 8 x - 9$ $f(color(red)(x))=8color(red)(x)-9$
to find $f (- 2)$ $f(color(blue)(-2))$ replace $x$ $x$ in the equation with $(- 2)$ $(color(blue)(-2))$
(and remember that $8 x$ $8x$ means $8 \times x$ $8xx x$ )

$f (- 2) = 8 \times (- 2) - 9$ $f(color(blue)(-2))= 8xx(color(blue)(-2))-9$
$XXxX = - 16 - 9$ $color(white)("XXxX")=-16 -9$
$XXXx = - 25$ $color(white)("XXXx")=-25$

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