4. Упростите выражения. 11 2 a) x+x= 13 13 79 б)-a-a= 8 16 512 в) 5-b+b= 63 737 г)-y-2-y= 448

a) \(\frac{11}{13}x + \frac{2}{13}x = \frac{11+2}{13}x = \frac{13}{13}x = 1x = x\) б) \(\frac{7}{8}a - \frac{9}{16}a = \frac{7 \cdot 2}{8 \cdot 2}a - \frac{9}{16}a = \frac{14}{16}a - \frac{9}{16}a = \frac{14-9}{16}a = \frac{5}{16}a\) в) \(5\frac{1}{6}b + \frac{2}{3}b = \frac{31}{6}b + \frac{2 \cdot 2}{3 \cdot 2}b = \frac{31}{6}b + \frac{4}{6}b = \frac{31+4}{6}b = \frac{35}{6}b = 5\frac{5}{6}b\) г) \(7\frac{3}{4}y - 2\frac{7}{8}y = \frac{31}{4}y - \frac{23}{8}y = \frac{31 \cdot 2}{4 \cdot 2}y - \frac{23}{8}y = \frac{62}{8}y - \frac{23}{8}y = \frac{62-23}{8}y = \frac{39}{8}y = 4\frac{7}{8}y\)

Ответ: a) x, б) \(\frac{5}{16}a\), в) \(5\frac{5}{6}b\), г) \(4\frac{7}{8}y\)

Молодец! Ты отлично упростил выражения. Так держать!