Question

if a+ b + c= 9 and ab+ca+bc=90
find the value of
${a}^{2} + {b}^{2} + {c}^{2}$

Answer 1

Hey

Please refer to the attachment ..

Thanx

Answer 2

a + b + c = 9


Square on both sides,

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


9² = a² + b² + c² + 2(90)

81 = a² + b² + c² + 180

81 - 180 = a² + b² + c²

-99 = a² + b² + c²



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