1) -0,5 : 2/3 - (-0,5) * 2/3 = -5/12
-1/2 : 2/3 = -3/4
-0,5 * 2/3 = -1/3
-3/4 + 1/3 = -5/12
2) 2/7 + (-4/9) : 2/7 - (-4/9) = -11/63
-4/9 : 2/7 = -5/9
2/7 - 5/9 = -17/63
-17/63 + 4/9 = -11/63
1) X = 357 - 624 + 276
X = 9
2) 357 - X + 218 = 128
357 + 218 - 128 = X
X = 447
Р=(а+в)*2
40/2-12=8 см-ширина прямоугольника
<span>НОД(45 и 56)=1.
НОД(12,18 и 24)=6.
вот :)</span>