Answer
$2x^2+xy-21y^2$
Work Step by Step
$$(x-3y)(2x+7y)$$
To multiply two binomials (expressions with two terms) multiply each term in the first binomial by each term in the second binomial:
$$=(x\times 2x)+(x\times 7y)+(-3y\times 2x)+(-3y\times 7y)$$ $$=2x^2+7xy-6xy-21y^2$$
Combine like terms:
$$=2x^2+xy-21y^2$$
