Question

(3a-7b-c)raise to power 2

Answer 1

9a square-49 b square-c square

Answer 2

$\longrightarrow \huge\sf{{(3a-7b-c)}^{2}}$

$\huge{\underline{\tt{\green{Simplification-}}}}$

Given : $\sf{a = 3a}$

$\sf{b = -7b}$

$\sf{c = c }$

${\underline{\tt{\orange{{Main\:Identity: (a+b+c)}^{2}={a}^{2}+{b}^{2}+{c}^{2}+2ab+2bc+2ca}}}}$

$\longrightarrow \sf{{(a-b-c)}^{2}={a}^{2}+{b}^{2}+{c}^{2}-2ab-2bc-2ca}$

$\longrightarrow \sf{{(3a-7b-c)}^{2}={3a}^{2}+{7b}^{2}+{c}^{2}-2\times\:3a\times\:7b+2\times\:7b\times\:c-2\times\:c\times\:3a}$

$\longrightarrow \sf\blue{{9a}^{2}+{4ab}^{2}+{c}^{2} = 42ab+14bc-16ca}$