Question

因式分解(a-2b-3c)^2

应该是计算。。。。
（2y-1)(4y+1)(2y+1)

Answer 1

(a-2b-3c)^2
=(a-2b)^2-6c(a-2b)+9c^2
=(a-2b)^2-6ac+12bc+9c^2
=a^2-4ab+b^2-6ac+12bc+9c^2

（2y-1)(4y^2+1)(2y+1)
=（2y-1)(2y+1)(4y^2+1)
=（4y^2-1)(4y^2+1)
=16y^2-1

Answer 2

1. (a-2b-3c)^2
=(a-2b)^2-6c(a-2b)+9c^2
=(a-2b)^2-6ac+12bc+9c^2
=a^2-4ab+4b^2-6ac+12bc+9c^2
=a^2+4b^2+9c^2-4ab-6ac+12bc
2.（2y-1)(4y+1)(2y+1)
=(4y^2-1)(4y+1)
=16y^3+4y^2-4y-1