Write the Following in Expanded Form
\[ (2a – 3b – c)^2 \]
Solution:
Using identity:
\[ (x-y-z)^2 = x^2+y^2+z^2-2xy+2yz-2xz \]
\[ (2a – 3b – c)^2 \]
\[ = (2a)^2 + (3b)^2 + c^2 – 2(2a)(3b) + 2(3b)(c) – 2(2a)(c) \]
\[ = 4a^2 + 9b^2 + c^2 – 12ab + 6bc – 4ac \]