1 . x2+y2+z2=2, xy+yz+zx=1

• A. 12
• B. 19
• C. 16
• D. 14

Answer: Option D

Explanation:

2 . x2+y2+z2=4,x+y-z=8

• A. $-60$
• B. $-30$
• C. $30$
• D. $60$

Answer: Option B

Explanation:

3 . x2+y2+z2=4,x+y-z=8

• A. -60
• B. -30
• C. 30
• D. 60

Answer: Option B

Explanation:

4 . x2+y2+z2=2,x+y+z=2

• A. 0
• B. 1
• C. 2
• D. 3

Answer: Option C

Explanation: