2.我們定義:如果兩個(gè)多項(xiàng)式M與N的和為常數(shù),則稱(chēng)M與N互為“對(duì)消多項(xiàng)式”,這個(gè)常數(shù)稱(chēng)為它們的“對(duì)消值”.如MF=2x
2-x+6與N=-2x
2+x-1互為“對(duì)消多項(xiàng)式”,它們的“對(duì)消值”為5.
(1)下列各組多項(xiàng)式互為“對(duì)消多項(xiàng)式”的是
(填序號(hào)):
①3x
2+2x與3x
2+2;
②x-6與-x+2;
③-5x
2y
3+2xy與5x
2y
3-2xy-1.
(2)多項(xiàng)式A=(x-a)
2與多項(xiàng)式B=-bx
2-2x+b(a,b為常數(shù))互為“對(duì)消多項(xiàng)式”,求它們的“對(duì)消值”;
(3)關(guān)于x的多項(xiàng)式C=mx
2+6x+4與D=-m(x+1)(x+n)互為“對(duì)消多項(xiàng)式”,“對(duì)消值”為t.若a-b=m,b-c=mn,求代數(shù)式a
2+b
2+c
2-ab-bc-ac+2t的最小值.