Factor
4(6x + 8) + (3x^2 + 4x) =
24x + 32 + 3x^2 + 4x =
3x^2 + 28x + 32 =
(3x + 4)(x + 8)
4(6x + 8) + (3x^2 + 4x)
= 24x + 32 + 3x^2 + 4x
= 3x^2 + 28x + 32
$$\\4(6x+8)+(3x^2+4x)\\\\=4(6x+8)+x(3x+4)\\\\=4\cdot 2(3x+4) + x(3x+4)\\\\=8(3x+4) + x(3x+4)\\\\=(3x+4)(8 + x)$$