What is $3 [f (x + 2)]$ $3[f(x + 2)]$ if $f (x) = x^{3} + 2 x^{2} - 4$ $f(x) = x^3 + 2x^2 - 4$ ?

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Answer 1 · 2017-11-06T16:13:43

I tried this:

You substitute your function with $x + 2$ $x+2$ instead of $x$ $x$ to get:

$3 [{(x + 2)}^{3} + 2 {(x + 2)}^{2} - 4] =$ $3[color (red)((x+2)^3+2(x+2)^2-4)]=$

$= 3 [x^{3} + 6 x^{2} + 12 x + 8 + 2 x^{2} + 8 x + 8 - 4] =$ $=3[x^3+6x^2+12x+8+2x^2+8x+8-4]=$

$= 3 [x^{3} + 8 x^{2} + 20 x + 12] =$ $=3[x^3+8x^2+20x+12]=$

$= 3 x^{3} + 24 x^{2} + 60 x + 36$ $=3x^3+24x^2+60x+36$

What is 3[f(x+2)]3[f(x + 2)] if f(x)=x3+2x2−4f(x) = x^3 + 2x^2 - 4?