Question

If a^2+b^2+c^2=125 and ab+bc+ca=50,then evaluate (a+b+c)

Answer 1

${(a + b + c) }^{2} = {a}^{2} + {b}^{2} + {c}^{2} +2 (ab + bc + ca) \\ {(a + b + c)}^{2} = 125 + 2(50) \\ ( {(a + b + c)}^{2} = 225 \\ a + b + c = 15$

This is your required solution.

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