Maths question

4(y-2z)(2z+3y)
=4(y)+(4)(-2z)+4(2z)+4(3y)
第一步已經錯了
括號要逐個拆
應用如下的步驟：

4(y-2z)(2z+3y)
= [4(y) – 4(2z)] (2z+3y)
= (4y – 8z)(2z + 3y)
= 4y(2z + 3y) – 8z(2z + 3y)
= 4y(2z) + (4y)(3y) – 8z(2z) – 8z(3y)
= 8yz + 12y^2 – 16z^2 – 24zy
= 12y^2 – 16z^2 – 16zy

4(y-2z)(2z+3y)=(4y-8z)(2z+3y)
= (8yz+12y^2-16z^2-24yz)
= 12y^2-16yz-16z^2
= 4(3y^2-4yz-4z^2)
=4(3y+2z)(y-2z)

你想計咩?
如果要最簡既就係抽個16出黎
16(y2-z2)

It has some wrong........
4(y-2z)(2z+3y)
=(4y-8y)(2z+3y)
=8zy+12y^2-16zy-24y^2
=-12Y^2-8ZY

錯左la~第1步就錯左la~
4(y-2z)(2z+3y)
=(4y-8y)(2z+3y)
=8zy+12y^2-16zy-24y^2
=-12Y^2-8ZY