When finding a product means we are multiplying
(3x+2)(3x+5) to multiply this we need to FOIL
(3x)(3x) FIRST - [tex]9 x^{2} [/tex]
(3x)(5) OUTER - 15x
(2)(3x) INNER - 6x
(2)(5) LAST - 10
so now we combine like terms - [tex]9 x^{2} +15x+6x+10[/tex] turns into [tex]9 x^{2} +21x+10[/tex]