Using the distributive property, we can expand the left side of the equation:

2x^2 - 4x + 2x - 4 = 0

Simplifying, we get:

2x^2 - 2x - 4 = 0

Dividing both sides by 2, we get:

x^2 - x - 2 = 0

Now we can use the quadratic formula to solve for x:

x = (-b ± sqrt(b^2 - 4ac)) / 2a

In this case, a = 1, b = -1, and c = -2. Plugging in these values, we get:

x = (1 ± sqrt(1 - 4(1)(-2))) / 2(1)

Simplifying under the square root:

x = (1 ± sqrt(9)) / 2

x = (1 ± 3) / 2

So the solutions are:

x = 2 or x = -1

Therefore, the equation (x + 1)(2x - 4) = 0 is true when x is equal to 2 or -1.