Вправи: 746

746. Спростіть вираз:

1) 9a2- 42a2- 5a+2 • a-23a+2 + a-11-2a = 3a-23a+2 (a-2)2a-2a- 12(3a+2) + a-11-2a = 3a-22a-1 – a-12a-1 = 3a-2-a+12a-1 = 2a-12a-1 = 1;

2) b-4b3- b : (b-12b2+ 3b+1 – 1b2- 1) = b-4b(b2- 1) : (b-12b+1(b+ 12) – 1b-1(b+1)) = b-4b(b2- 1) : (b- 1\n-1b+1(2b+1) – 1\2b+1b-1(b+1)) = b-4b(b2- 1) : b2- 2b+1-2b-12b+1b+1(b-1) = b-42b+1(b2- 1)bb2- 1(b2- 4b) = b-4(2b+1)b • b(b-4) = 2b+1b2;

3) (c+2c2- c-6 – 2cc2- 6c+9) : c2+ 3c(2c-6)2 = (c+ 2\c-2c-3(c+2) – 2c\c+2(c-3)2) : c(c+3)4(c-3)2 = c2- c-6-2c2- 4c(c-3)2(c+2) : c(c+3)4(c-3)2 = -c2- 5c-6•4(c-3)2(c-3)2c+2•c(c+3) = -4c+3(c+2)cc+2(c+3) = –4c.