Step-by-step explanation:
a)
[tex](3x-4y+2z)^2\\=9x^2+16y^2+4z^2+2.3.(-4)xy+2.3.2xz+2.(-4).2yz\\=9x^2+16y^2+4z^2-24xy+12xz-16yz[/tex]
b)
[tex](4a+1)^3\\= 64a^3+3.(4a)^2.1+3.4a.1^2+1\\=64a^3+48a^2+12a+1\\[/tex]