RESOLVER:
a) [tex]\left(7x+6\right)\left(2x\right)[/tex]
[tex]=\left(2x\right)\left(7x+6\right)[/tex]
[tex]=2x\cdot \:7x+2x\cdot \:6[/tex]
[tex]\boxed{=14x^2+12x}[/tex] (I) INCORRECTO
b) [tex]x\left(3x^3+2y^2\right)[/tex]
[tex]=x\cdot \:3x^3+x\cdot \:2y^2[/tex]
[tex]\boxed{=3x^4+2xy^2}[/tex] (C) CORRECTO
c) [tex]\left(2x-1\right)\left(2x+1\right)[/tex]
[tex]=\left(2x\right)^2-1^2[/tex]
[tex]\boxed{=4x^2-1}[/tex] (I) INCORRECTO
d) [tex]5xy^3\left(x^4+2y^5\right)[/tex]
[tex]=5xy^3x^4+5xy^3\cdot \:2y^5[/tex]
[tex]\boxed{=5x^5y^3+10xy^8}[/tex] (I) INCORRECTO
[tex]BUENA\:\:SUERTE[/tex]
