\begin{align*}
\StrSubstitute{ (2*x + 7)*(7*x + 4) }{*}{}  & = \StrSubstitute{ 14*x**2 + 57*x + 28 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (-4*x + 3)*(-4*x + 7) }{*}{}  & = \StrSubstitute{ 16*x**2 - 40*x + 21 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (-8*x - 4)*(-8*x + 3) }{*}{}  & = \StrSubstitute{ 64*x**2 + 8*x - 12 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (5*x - 9)*(7*x + 3) }{*}{}  & = \StrSubstitute{ 35*x**2 - 48*x - 27 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (-9*x + 7)*(-2*x - 7) }{*}{}  & = \StrSubstitute{ 18*x**2 + 49*x - 49 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (4*x + 8)*(6*x - 8) }{*}{}  & = \StrSubstitute{ 24*x**2 + 16*x - 64 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (3*x - 6)*(7*x + 8) }{*}{}  & = \StrSubstitute{ 21*x**2 - 18*x - 48 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (-7*x - 8)*(4*x - 7) }{*}{}  & = \StrSubstitute{ -28*x**2 + 17*x + 56 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (-7*x + 3)*(3*x + 8) }{*}{}  & = \StrSubstitute{ -21*x**2 - 47*x + 24 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\StrSubstitute{ (-4*x + 4)*(5*x + 9) }{*}{}  & = \StrSubstitute{ -20*x**2 - 16*x + 36 }{**}{^}[\result]\StrSubstitute{\result}{*}{}\\
\end{align*}