9 = 2(2x + 4)2, 9 = 2(4x2 + 16x + 16), 9 = 8x2 + 32x + 32 How did the 16x come about?

9 = 2(2x + 4)

^{2}- n
^{2}= (n)(n)

- Using the distributive property of multiplication (a + b)(c + d) = ac + ad + bc + bd
- We sometimes refer to this as FOIL (First, Outer, Inner, Last)

9 = 2(4x

^{2}+ 8x + 8x + 16)9 = 2(4x

^{2}+ 16x + 16)- Now distribute the 2

^{2}+ 32x + 32

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## Comments

^{2}) + (8x) + (8x) + (16) ]