Question 339029
{{{(5x+2y+3)(5x+2y-3)=(5x+2y+3)*(5x)+(5x+2y+3)*(2y)+(5x+2y+3)*(-3)}}}
{{{(5x+2y+3)(5x+2y-3)=(25x^2+10xy+15x)+(10xy+4y^2+6y)+(-15x-6y-9)}}}
{{{(5x+2y+3)(5x+2y-3)=25x^2+4y^2+20xy-9}}}