... -4 ,25 Bài 21 /36:43xyz 2 + 2 1xyz 2 + -41xyz 2 = (43 + 2 1 - 41) xyz 2 = 1 xyz 2 hệ số: 1phần biến: xyz 2 bậc: 4Bài 23 /36:a/ 3x 2 y + 2x 2 y = 5x 2 yb/ -5x 2 – 2x 2 = -7x 2 c/ 2x5 ... x 2 y + 2x 2 y= ( -2 + 5 + 1 + 1)x 2 y= 6x 2 y bậc 3Bài 19/36:16x 2 y5 – 2x3y 2 ; x = 0,5; y = -1= 16.0,5 2 .(-1)5 – 2. 0,53.(-1) 2 = 16.0 ,25 .(-1) – 2. 0, 125 .1=- 4 – 0 ,25 = -4 ,25 Bài ... – 3= 4x 2 y – 2xy – 3 ?2 Q = 5x 2 y – 3xy + 2 1x 2 y – xy + 5xy - 31x+ 2 1 + 3 2 x - 41= (5 + 2 1)x 2 y + (-3 – 1 + 5)xy + (3 2 - 31)x + 2 1 - 41= 2 11 x 2 y + xy +...