Вправи: 189

189. Спростіть вираз:

1) 29a2 • 18 = 29a2 • 181 = 2 •189a2 •1 = 4a2;

2) 27b • 28b² = 27b • 28b21 = 2 • 28b27b •1 = 8b;

3) 215x • (–24x³) = 215x • (–24x31) = –2 • 24x315x •1 = –16x25;

4) (a + 2) • 92+a = a+21 • 92+a = a+2•91 •(2+a) = 9;

5) (3b – 12) • 44-b = 3b-121 • 44-b = 3b-12•41 •4-b = 3b-4•44-b = –3b-4•4b-4 = –12;

6) (a – 4a²) • (–54a-1) = a-4a21 • (–54a-1) = –(a-4a2) •51 •(4a-1) = –a1-4a•54a-1 = a •a-1•54a-1 = 5a