1.
If the system of equations
x+4y−z=λx + 4y - z = \lambda

7x+9y+μz=−37x + 9y + \mu z = -3

5x+y+2z=−15x + y + 2z = -1

has infinitely many solutions, then (2μ+3λ)(2\mu + 3\lambda) is equal to: