If x + y + z = 2, x3 + y3 + z3 - 3xyz = 74, then (x2 + y2 + z2 ) is equal to :
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 26
a3 + b3 + c3 - 3abc = (a + b + c)/2 [3(a2 + b2 + c2) - (a + b + c)2]
2/2 [3(x2 + y2 + z2) - 22] = 74
3(x2 + y2 + z2) = 74 + 4
x2 + y2 + z2 = 78/3 = 26