Gary works at a bakery, and he needs to select a rectangular cookie sheet with an area of 192 square inches. The area of the cookie sheet is represented by the expression given below.

x² + 4x

Complete the given statements, and find the width of the cookie sheet.

Step 1: x² + 4x = 192
Step 2: x(x + ___ ) = 192 The length is x. The width is ___
Step 3: x² + 4x = 192 = 0
Step 4: (x + ___ ) (x - 12) = 0
Because the length can't be ___, the length is 12, and the width is ___

Here is the selection of values that can be inserted into the blank spaces. Note that not all of them will be used.
12
4
x
x + 4
-16
16
x + 12
x²