Answer
$6x^2+61xy+63y^2$
Work Step by Step
$$(x+9y)(6x+7y)$$
To multiply two binomials (expressions with two terms) multiply each term in the first binomial by each term in the second binomial:
$$=(x\times 6x)+(x\times 7y)+(9y\times 6x)+(9y\times 7y)$$ $$=6x^2+7xy+54xy+63y^2$$
Combine like terms:
$$=6x^2+61xy+63y^2$$
