[tex]3a)\\\\3a+2a*5a-7a^2+\frac{6a^2}{3}=3a+10a^2-7a^2+2a^2=5a^2+3a\\\\b)\\\\3x^2+2x*(-3x)+4x^2+\frac{15x}{3}=3x^2-6x^2+4x^2+5x=x^2+5x\\\\c)\\\\-4y*5x+2x*5-3x*2y+\frac{8xy}{2}=-20xy+10x-6xy+4xy=10x-22xy\\\\d)\\\\\frac{10ab}{5} +5b^2-2b*5b-3b^2*2-2ab=2ab +5b^2-10b^2-6b^2 -2ab=-11b^2[/tex]
