## Intermediate Algebra (12th Edition)

$49x^2+42xy+9y^2$
$\bf{\text{Solution Outline:}}$ Use the special product on squaring binomials to simplify the given expression, $(7x+3y)^2 .$ $\bf{\text{Solution Details:}}$ Using the square of a binomial which is given by $(a+b)^2=a^2+2ab+b^2$ or by $(a-b)^2=a^2-2ab+b^2,$ the expression above is equivalent to \begin{array}{l}\require{cancel} (7x)^2+2(7x)(3y)+(3y)^2 \\\\= 49x^2+42xy+9y^2 .\end{array}