We have, [tex](2r+3)(3r^2+4r+5)[/tex] or more generally,
[tex](a+b)(c+d+e)=ac+ad+ae+bc+bd+be[/tex]
So using that, we find,
[tex](2r+3)(3r^2+4r+5)=6r^3+8r^2+10r+9r^2+12r+15[/tex], then collect terms with same exponent and get [tex]\boxed{6r^3+17r^2+22r+15}[/tex].
