Question

plsss answer it......

Answer 1

This is the answer I dont no it is correct or not check it

Answer 2

hey,

here is the answer u have wanted.

first let's start learning the formula.
which is



${a}^{2} + {b}^{2} + {c}^{2} + 2(ab + bc + ca) = {a + b + c}^{2}$
$a + b + c = 13$
${a}^{2} + {b}^{2} + {c}^{2} is \: 15$
ab + bc + ca=?
if we substitute we get,
${13}^{2} = 15 + 2ab +2 bc +2 ac$
as we know
${13}^{2} is169$
169=15+2(ab+bc+ca)
169-15=2(ab+bc+ca)
154=2(ab+bc+ca)
154/2=ab+bc+ca
77= ab+bc+ca

hope this helps you
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sid071