दो समतलो `3x - 6y + 2z = 7` और `2x + 2y - 2z = 5` के बीच के कोण ज्ञात कीजिए |

x+y+z=6 x + 2z =7, 3x + y + z = 12

Find the angle between the planes : (i) 3 x - 6y - 2z = 7 " " 2x + y - 2z = 5 (ii) 4 x + 8y + z = 8 " " and y + z = 4 (iii) 2 x - y + z =6 " " and x + y + 2z = 7 .

Add: 5x - 8y + 2z, 3z - 4y - 2x, 6y - z - x and 3x - 2z - 3y

2x + 3y-5z = 7, x + y + z = 6,3x-4y + 2z = 1, then x =

Add 2x - 3y + z , 5y - x + 7z and 3x - y - 6z.

The lines x + y + z - 3 = 0 = 2x - y + 5z - 6 and x - y - z + 1 = 0 = 2x + 3y + 7z - k are coplanar then k equals