Place the indicated product in the proper location on the grid (x + 0.2)(x - 0.2)

these are the factors of a difference of squares

a² - b² = (a + b )(a - b ), hence

(x + 0.2 )(x - 0.2 ) = x² - 0.2² = x² -0.04

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.