Подставим значение b = 10 в каждое выражение и вычислим:
a)
$$\frac{6+b}{2} = \frac{6+10}{2} = \frac{16}{2} = 8$$b)
$$\frac{5b+12}{4} = \frac{5 \cdot 10 + 12}{4} = \frac{50 + 12}{4} = \frac{62}{4} = \frac{31}{2} = 15.5$$c)
$$\frac{b-2}{6} = \frac{10-2}{6} = \frac{8}{6} = \frac{4}{3} = 1\frac{1}{3}$$d)
$$\frac{3b-10}{5} = \frac{3 \cdot 10 - 10}{5} = \frac{30 - 10}{5} = \frac{20}{5} = 4$$e)
$$\frac{6+5b}{8} = \frac{6 + 5 \cdot 10}{8} = \frac{6 + 50}{8} = \frac{56}{8} = 7$$f)
$$\frac{50-3b}{7} = \frac{50 - 3 \cdot 10}{7} = \frac{50 - 30}{7} = \frac{20}{7} = 2\frac{6}{7}$$g)
$$\frac{7+4+4b}{3} = \frac{11 + 4 \cdot 10}{3} = \frac{11 + 40}{3} = \frac{51}{3} = 17$$h)
$$\frac{10+5b-6}{2} = \frac{4 + 5 \cdot 10}{2} = \frac{4 + 50}{2} = \frac{54}{2} = 27$$Ответ:
a) 8
b) 15.5
c) $$1\frac{1}{3}$$
d) 4
e) 7
f) $$2\frac{6}{7}$$
g) 17
h) 27