Question

i) If a + b + c = 9 and ab + c + ca = 26 find a2 + b2 + c2

ii) If x + y + z = 0 show that x3 + y3 + z3 = 3xyz​

Answer 1

Answer:

i)a+b+c=9

Squaring on both the sides

(a+b+c)²=(9)²

a²+b²+c²+2ab+2bc+2ca=81

a²+b²+c²+2(ab+bc+ca)=81

a²+b²+c²+2(26)=81

a²+b²+c²+52=81

a²+b²+c²=81-52

a²+b²+c²=29