Question

Please answer this question

a + b + c = 12
a^2 + b^2 + c^2 = 64
Let ab + bc + ca​

Answer 1

$\huge{\underline{\underline{\mathfrak{\bigstar{\red{Answer{\bigstar}}}}}}}$

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

$\sf{(12 {)}^{2} = 64 + 2ab + 2bc + 2ca}$

$\sf{144 = 64 + 2(ab + bc + ca)}$

$\sf{144 - 64 = 2(ab + bc + ca)}$

$\sf{80 = 2(ab + bc + ca)}$

$\sf{40 = ab + bc + ca}$

$\sf{\red{ab + bc + ca = 40}}$

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