Answer
$14x^2-x-3$
Work Step by Step
RECALL
For any real numbers a, b, and c:
$a(b+c)=ab + ac
\\AND
\\a(b-c) =ac-bc$
Use the distributive property (which is shown above) to obtain:
$=2x(7x+3) - 1(7x+3)
\\=2x(7x)+2x(3) -1(7x) -1(3)
\\=14x^2+6x-7x-3
\\=14x^2+(6-7)x-3
\\=14x^2+(-1)x-3
\\=14x^2-x-3$
