Вправи: 189

189. Спростіть вираз:

(18y2+ 3y27y3- 1 – 3y+19y2+ 3y+1) : (1 – 3y-1y – 5-6y3y-1) = –y.

1. 18y2+ 3y3y-1(9y2+ 3y+1) – 3y+ 1\3y-19y2+ 3y+1 =18y2+ 3y-3y-1(3y+1)3y-1(9y2+ 3y+1) = 18y2+ 3y-9y2+ 13y-1(9y2+ 3y+1) = 18y2+ 3y -(9y2- 1)3y-1(9y2+ 3y+1) = 9y2+ 3y+13y-1(9y2+ 3y+1) = 13y-1;

2. 1^\y(3y–1) – 3y- 1\3y-1y – 5-6y\y3y-1=y3y-1- (3y-1)2- y(5-6y)y(3y-1) = 3y2- y-9y2- 6y+1- 5y+6y2y(3y-1) = -1y(3y-1);

3. 13y-1 : –1y(3y-1) = –1 •y(3y-1)3y-1•1 = –y.