Question

If 7x + 6y – 2z = 0

3x + 4y + 2z = 0

x – 2y – 6z = 0 then which option is correct

(1) no. solution

(2) only trivial solution

(3) Infinite non trivial solution for x = 2z

(4) Infinite non trivial solution for y = 2z 

Answer 1

Answer is (3)

= 7(–20) – 6(–20) – 2(–10) 

= – 140 + 120 + 20 = 0 

so infinite non-trivial solution exist 

now equation (1) + 3 equation (3)

10x – 20z = 0

x = 2z