Algebra: A Combined Approach (4th Edition)

$x^2+14x+49$
A binomial squared is equal to the square of the first term plus or minus twice the product of both terms plus the square of the second term. $(a - b)^2= a^2 - 2ab + b^2$ $(x+7)^2=x^2+2(x)(7)+7^2=x^2+14x+49$