Question

If a2 + b2 + c2 = 125 and ab + bc + ca = 50, find a + b + c.
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Answer 1

Hi friend here is your answer.

Given : a²+b²+c²=125

ab+bc+ca=50

Too find : a+b+c=?

$we \: knew \: .. \\ (a + b + c) {}^{2} = {a}^{2} + {b}^{2} + {c}^{2} + 2(ab + bc + ca) \\ (a + b + c) {}^{2} = 125 + 2(50) \\ (a + b + c) {}^{2} = 125 + 100 \\ (a + b + c) {}^{2} = 225 \\ (a + b + c) = \sqrt{225} \\ (a + b + c) = 15$

Hope my answer will help you.

Answer 2

Answer:

we know that

(a+b+c)²=a²+b²+c²+2(ab+ bc +ac)

(a+ b+ c)²=125 +2(50)

(a +b+ c)²=125+100

(a +b +c)²=225

a+b+c=√225

a+b+c=15