First, distribute 4:
[tex](4x - 4)(x + 4)[/tex]
Factor using FOIL:
[tex]4x \times x + 4x \times 4 - 4 \times x - 4 \times 4[/tex]
Simplify:
[tex]4 {x}^{2} + 16x - 4x - 16[/tex]
Combine like terms:
[tex]4 {x}^{2} + 12x - 16 = 0[/tex]
That is your factored or standard form.