Answer
$12x^2-x-35$
Work Step by Step
Using $(a+b)(c+d)=ab+ad+bc+bd$ or the FOIL Method, the product of the given expression, $
(3x+5)(4x-7)
,$ is
\begin{array}{l}\require{cancel}
3x(4x)+3x(-7)+5(4x)+5(-7)
\\\\=
12x^2-21x+20x-35
\\\\=
12x^2-x-35
.\end{array}