1)(х-3)(х-7)-2х(3х-5)=x^2-7x-3x+21-6x^2+10x=-5x^2-10x+31
2)4а(а-2)-(а-4)²=4a^2-8a-(a^2-8a+16)=4a^2-8a-a^2+8a-16=3a^2-16
3)2(м+1)²-4м=2(m^2+2m+1)-4m=2m^2+4m+2
1)(х-3)(х-7)-2х(3х-5)=x^2-7x-3x+21-6x^2+10x=-5x^2-10x+31
2)4а(а-2)-(а-4)²=4a^2-8a-(a^2-8a+16)=4a^2-8a-a^2+8a-16=3a^2-16
3)2(м+1)²-4м=2(m^2+2m+1)-4m=2m^2+4m+2