(1)2x²-x-1 (2)(a+b)²+6(a+b)+8 (3)2(y+1)²+5(y+1)+2

(1)2x²-x-1 (2)(a+b)²+6(a+b)+8 (3)2(y+1)²+5(y+1)+2
(1)2x²-x-1 (2)(a+b)²+6(a+b)+8 (3)2(y+1)²+5(y+1)+2

(1)2x²-x-1 (2)(a+b)²+6(a+b)+8 (3)2(y+1)²+5(y+1)+2
原式=(2x+1)(x-1)
原式=(a+b+2)(a+b+4)
原式=[2(y+1)+1][(y+1)+2]
=(2y+3)(y+3)