Question

Expand (a-b-c) ^2
Please help.......​

Answer 1

${(a - b - c)}^{2}$

$(a - b - c)(a - b - c)$

$a(a - b - c) - b(a - b - c) - c(a - b - c)$

${a}^{2} - ab - ac - ab + {b}^{2} + bc - ac + bc + {c}^{2}$

${a}^{2} - 2ab - 2ac + 2bc + {b}^{2} + {c}^{2}$

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${a}^{2} + {b}^{2} + {c}^{2} - 2ab - 2ac + 2bc$