... =-5 +x2 -4 x3+x4-x6-Q(x)= 1-x-x2+x3+x4 -2 x5P(x)-Q(x) =-4 -x-3x3+2x4 -2 x4 -2 x5-x6Bài 52(46-sgk)P(x) =x2 -2 x-8P (-1 ) = (-1 )2 -2 (-1 )-8 =-5 P(0) = (0)2 -2 (0 )-8 =-8 P(4) = (4)2 -2 (4 )-8 ... 5x2+xyz-5xy+3-yM+N=(3xyz-3x2+5xy-1)+(5x2+xyz-5xy+3-y) = 4xyz +2x2-y+2M-N = (3xyz-3x2+5xy-1 )-( 5x2+xyz-5xy+3-y)= 2xyz +10xy- 8x2+y- 4N-M = -2 xyz- 10xy+ 8x2 - y+ 4?2Bài 29( 40-SGK)a. (x+y)+ (x-y) ... 2x5+5x4-x3+x2-x-1+x4-x3 -5 x-2 = 2x5+6x4 -2 x3+x2 -6 x-3.Cách 2.P(x) = 2x5+5x4-x3+x2-x-1-Q(x) = -x4+x3+5x+2P(x)-Q(x) = 2x5+6x4 -2 x3+x2 -6 x-3P(x) = 2x5+5x4-x3+x2-x-1 - Q(x) = x4-x3 -5 x-2P(x)-Q(x)...