Solve the following systems of equations. 1. 4x + 2y - 6z = -38 2. 2p - 5q +r = 1 5x - 4y+z=-18 3q + 2r =5 x + 3y + 7z = 38 1=-2 3. 3x = -12 4. 4xty= -7 2x - y + 3z =-1 x - 2z =4 3x +4-z=-7 3v + 2z = 8