Вправи: 18

18. Спростіть вираз:

1) 3,8 • 5а • (–7) = –133a;

2) –0,25b • 16k = –4k;

3) 2(3x – 4) + 5 = 6x – 8 + 5 = 6x – 3;

4) –6(2а – 4) + 3(7 – а) = –12a + 24 + 21 – 3a = –15a + 45;

5) 3 – 17у – 4(у + 13) = 3 – 17y – 4y – 13 = –21y – 10;

6) –4(m + n) + 6,8m + 1,8n = –4m – 4n + 6,8m + 1,8n = 2,8m – 2,2n;

7) 2,4 – (х – (2,6x – 6)) = 2,4 – (x – 2,6x + 6) = 2,4 – x + 2,6x – 6 = 1,6x – 3,6;

8) 5d – (4d – (3d – (2d – 1))) = 5d – (4d – 2d + 1)) = 5d – 4d + 2d – 1 = 3d – 1.