Question

An algebra tile configuration. Only the Product spot is shown. 9 tiles are in the Product spot in 5 columns with 5 rows. First row: 1 + x squared, 4 + x. Below the + x squared tile are 4 +x tiles.
Which value is needed in the expression below to create a perfect square trinomial?

x2+8x+______

4
8
16
64

Answer 1

16

Because to complete the square you take half the x‑coefficient (8/2 = 4) and square it: 4^2 = 16. Then x^2 + 8x + 16 = (x + 4)^2.