计算：(x-3y)(x-6y-1)= （3a-b)(3a+b+5)= 2x(x的2次幂-2x+3)-(x+5)(2x-3)= (解答过程完整）

计算：(x-3y)(x-6y-1)= （3a-b)(3a+b+5)= 2x(x的2次幂-2x+3)-(x+5)(2x-3)= (解答过程完整）
计算：(x-3y)(x-6y-1)= （3a-b)(3a+b+5)= 2x(x的2次幂-2x+3)-(x+5)(2x-3)= (解答过程完整）

计算：(x-3y)(x-6y-1)= （3a-b)(3a+b+5)= 2x(x的2次幂-2x+3)-(x+5)(2x-3)= (解答过程完整）
(x-3y)(x-6y-1)
=x²-6xy-x-3xy+18y²+3y
=x²-9xy-x+18y²+3y
(3a-b)(3a+b+5)
=9a²+3ab+15a-3ab-b²-5b
=9a²+15a-b²-5b
2x(x²-2x+3)-(x+5)(2x-3)
=2x³-4x²+6x-2x²-7x+15
=2x³-6x²-x+15