convert from factored form to standard form f(x)=\frac{1}{2}(x + 2)(x - 4)

: $f(x)=\frac{1}{2}x^{2}-x - 4$

Explanation:

Step1: Expand $(x + 2)(x - 4)$

Using FOIL method: $(x+2)(x - 4)=x^{2}-4x+2x - 8=x^{2}-2x - 8$

Step2: Multiply by $\frac{1}{2}$

$\frac{1}{2}(x^{2}-2x - 8)=\frac{1}{2}x^{2}-x - 4$