①3a(5a-2b) ②(x-3y) ×（-6x) ③化简x(x-1)+2x(x+1)-3x(2x-5)

/>(1)3a(5a-2b)=15a^2-6ab
(2)(x-3y)*(-6x)=-6x^2+18xy
(3)x(x-1)+2x(x+1)-3x(2x-5)=x^2-x+2x^2+2x-6x^2+15x=-3x^2+16x