② 次の式を展開しなさい。〔反復部分の置き換え] □(1)(x-y-z) (x-y+z) □(3)(x+3y-7)2 (5) (2x+y-3) (2x-y-3) □ (7) (x+y−1) (x −y+1) (9) (x-3y+2)(x+3y-2) (2) (x+2y-6) (x+2y−2) □ (4) (2x-y+4) 2 □(6)(x+3+y) (x-5+y) □ (8) (2x-3y+1) (2x+3y−1) ☐ □ (10) (4x−y+1) (4x+y−1)

2 (1) x²-2xy + y² −z² (3) x²+6xy+9y²-14x-42y+49 (5) 4x²-12x+9-y² (7) x²-y²+2y-1 (9) x²— 9y²+12y — 4 3 (1) 5+4√√2 (2) -1-√√5 (5) 19+8√√3 (9)2 (6) 5+2√6 (10)5 (2) x²+4xy+4y²-8x-16y+12 (4) 4x²-4xy+y²+16x-8y+16 (6) x²+2xy + y²-2x-2y-15 (8) 4x2 9y+6y-1 (10) 16x2 y2+2y-1 (3)9-4√6 (7) 14-6√√5 (11)3 (4) −1+√√6 (8) 24-12√3 (12)8