Answers

2016-06-14T17:56:23+08:00
This is a common special product, which is the square of a binomial.

Sol 1. Using the FOIL method,

First:   a · a = a²
Outer: a · 3 = 3a
Inner:  3 · a = 3a
Last:   3 · 3 = 9

(a+3)(a+3) = a² + 6a + 9

Sol 2. Special Product

(a + b)² = a² + 2a + b²
(a + 3)² = a² + 2·3·a + 3² = a² + 6a + 9

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Omg thank you thanks for help
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