Question

if n+b+c=7 and ab+bc+ca=21 then find yhe value of A2+b2+c2​

Answer 1

Answer:

7

Step-by-step explanation:

(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca

7square-2×21=answer

answer=49-42=7

Answer 2

7

Step-by-step explanation:

Given:

a+b+c = 7

ab+bc+ac = 21

To Find :

a²+b²+c²

How to find ?

So, Easy Answer in 3 steps

1)Square the both sides of [a+b+c = 7]

2) Then, Substitute the values

3) Simplify and get answer

$\large \text{ \blue{Hard} ? \red{Not} at All}$

Solution :

${(a +b + c)}^{2} = 7 {}^{2} \\ \\ {a}^{2} + {b}^{2} + {c}^{2} + 2(ab + bc + ac) = 49 \\ \\ {a}^{2} + {b}^{2} + {c}^{2} = 49 - 2.21 \\ \\ {a}^{2} + {b}^{2} + {c}^{2} = 49 - 42 = 7$

Therefore, The required answer is 7