Вправи: 1229

1229. Спростіть вираз:

1) (2х – у – 3) • (–2) – 4(х – 2у) = –4x + 2y + 6 – 4x + 8y = 10y – 8x + 6;

2) 2х(а – 3b + 5с) – х(2а – 4b) = 2xa – 6xb + 10xc – 2xa + 4xb = 10xc – 2xb;

3) 138c – 214c + 512c = 118c – 94c + 512c = 118c – 188c + 512c = –78c + 512c = –2124c + 1024c = –1124c;

4) –(135a + 37b) + 3(–1715a + 17b) = –85a – 37b – 225a + 37b = –305a = –6a.