2) [tex]36 - m^{2} - 3m + m^{2} = 36-3m[/tex]

1) [tex]25x^{2} +30xy+9y^{2} - (6x^{2} -18xy-3xy+9y^{2}) = 25x^{2} +30xy+9y^{2} - 6x^{2} +21xy-9y^{2} = 19x^{2} +51xy[/tex]