Question

If a+b+c = 12 ,
ab+bc+ca = 10 , Find a²+b²+c² .

Answer 1

(a+b+c)² = a²+b²+c² +2(ab+bc+ca)

(12)² = a²+b²+c² +2(10)

(12)² =a²+b²+c² +20

144-20 = a²+b² +c²

124= a²+b²+c²


I hope this will help you


-by ABHAY

Answer 2

$(a + b + c) ^{2} = a^{2} + {b}^{2} + {c}^{2} \\ + 2(ab + bc + ca) \\ {12}^{2} = {a}^{2} + {b}^{2} + {c}^{2} + 2 \times 10 \\ 144 - 20 = a^{2} + {b}^{2} + {c}^{2} \\ 124$
answer is 124
hope you understand