Question

Q26. If a +b+c=9 and ab + bc + ca=3, find a2 + b2 + c2​

Answer 1

Answer:

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

a2+b2+c2=9^2 -2×3

=81-6

=75

Answer 2

Answer:

(a+b+c)²= a²+b²+c²+2(ab+bc+ca)

9²=a²+b²+c²+2*3

81=a²+b²+c²+6

81-6=a²+b²+c²

75=a²+b²+c²