Verified answer

a,b цифры

0.(a) = a/9

0.(b) = b/9

0.a = a/10

0.b = b/10

a.(a) = a + 0.(a) = a + a/9 = 10/9a

b.(b) = b + 0.(b) = b + b/9 = 10/9b

1.

(a.(a) + b.(b))/(0.(a) + 0.(b)) = (10/9 a + 10/9b) / (a/9 + b/9) = 10/9(a + b) / 1/9(a + b) = 10/9 * 9 = 10

ответ b

2.

(a.(a) + b.(b))/(0.a + 0.b) = (10/9a + 10/9b)/(a/10 + b/10) = 10/9(a + b) / 1/10(a + b) = 100/9  

ответ e)

3.

(0.a - 0.b) / (0.(a) - 0.(b)) = (a/10 - b/10) / (a/9 - b/9) = 1/10(a - b) / 1/9(a - b) = 9/10 = 0.9  

ответ d)