#1**+3 **

(x + 1)^{2} = (x + 1)(x + 1)

Multiply each item in the first set of parenthesees by each item in the second set of parenthesees.

**(x + 1)(x + 1) = (x)(x) + (x)(1) + (1)(x) + (1)(1)**

Simplify.

(x)(x) + (x)(1) + (1)(x) + (1)(1) = x^{2} + 2x + 1

So....

(x + 1)^{2} = x^{2} + 2x + 1

hectictar May 14, 2019