Вправи: 147 (1-5)

147. Спростіть вираз:

1) 93+ x – x23+ x = 9- x23+ x = (3- x)(3+x)3+ x = 3 – x;

2) 25x-5 – x2x-5 = 25- x2x-5 = (5- x)(5+ x)x-5 = -(x-5)(5+ x)x-5 = –5 – x;

3) 366+ c – c26+ c = 36- c26+ c = (6- c)(6+ c)6+ c = 6 – c;

4) 7x2-49 – xx2-49 = 7- xx2-49 = 7- x(x-7)(x+7) = -(x-7)(x-7)(x+7) = – 1x+7;

5) y2y+1 + 1+2yy+1 = y2+1+2yy+1 = (y+1)2y+1 = y + 1;

6) 4+ c2c-2 – 4cc-2 = 4+ c2-4cc-2 = (c-2)2c-2 = c – 2;

7) 6x-3 + 2x3- x = 6x-3 – 2xx-3 = 6-2xx-3 = -(2x-6)x-3 = -2(x-3)x-3 = –2;

8) y22- y + 4y-2 = y22- y – 42- y = y2-42- y = (y-2)(y+2)2- y = -(2- y)(y+2)2- y = –y – 2;

9) 3+ c2c-1 + 41- c = 3+ c2c-1 – 4c-1 = 3+ c2-4c-1 = c2-1c-1 = (c-1)(c+1)c-1 = c + 1;

10) 5(c2+1)(c-1)2 + 10c(1- c)2 = 5c2+5+10c(c-1)2 = 5c2+10c+5(c-1)2.