Question

Expand (2x -5y -7z)²​

Answer 1

(2x - 5y - 7z)²

= (2x)² + (-5y)² + (-7z)² + 2(2x)(-5y) + 2(-5y)(-7z) + 2(-7z)(2x)

= 4x² + 25y² + 49z² - 20xy + 70yz - 28zx.

Answer 2

You can Use identity: (a+b+c)^2 = a^2 + b^2+ c^2 + 2ab + 2bc + 2ca