1.
Let the system of equations
x+5y−z=1x + 5y - z = 1

4x+3y−3z=74x + 3y - 3z = 7

24x+y+λz=μ24x + y + \lambda z = \mu

have infinitely many solutions. If x,y,zx, y, z are integers and satisfy 7x+y+z≤777x + y + z \leq 77, then the number of solutions of this system is: