Ответы §1 главы 2

451.
452.x + 4y - 2z = 2.
453.x + y = 2a
454.x - y + z = a
455.2y - 3z + 7 = 0.
456.3y + 2z = 0.
457.2x + y = 0.
458.
459.x + y + z = 4.
460.
462.
463.x - 2y - 3z + 14 = 0.
464.3x - 4z = 0.
465.x + y = 0.
466.