How do you find $f(-1)$ given $f(x)=2x+2$ ?

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Answer 1 · 2016-12-24T13:34:55

$f(color(red)(-1)) = 0$

To solve $f(-1)$ you need to substitute $color(red)(-1)$ for every occurrence of $color(blue)(x)$ in the function:

$f(color(blue)(x)) = 2color(blue)(x) + 2$

Giving:

$f(color(red)(-1)) = (2*color(red)(-1)) + 2$

$f(color(red)(-1)) = -2 + 2$

$f(color(red)(-1)) = 0$

How do you find f(-1)f(-1) given f(x)=2x+2f(x)=2x+2?