Question

expond the following (3x-5y-z)^2​

Answer 1

Answer:

the answer is

Answer 2

Using identity:(x+y+z)^2=x^2+y^2×z^2+2xy+2yz+2zx.

x=-3x, y=5y, z=-2z

=(-3x)^2+(5y)^2+(-2z)^2+2×(-3x)×5y+2×5y×(-2z )+2×(-2z)×(-3x)

=9x^2+25y^2+4z^2-30xy-20xy-12zx.