Question

Expand : (3a – 7b – c)2​

Answer 1

Step-by-step explanation:

(a+b+c)^2=a+b+c+2ab+2bc+2ca

use this formulae

Answer 2

Step-by-step explanation:

Identity:- a²+b²+c²+2ab+2bc+2ac

(3a)² + (-7b)² + (-c)² + 2×3a×-7b + 2×-7b×-c + 2×3a×-c

=9a² + 49b² + c² - 42ab + 14bc - 6ac

hope it helps

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