Answer:
74
Explanation:
a + b = 11
ab - ba = 27
10a + b - 10b - a = 27
10a - a + b - 10b = 27
9a - 9b = 27
9(a - b) = 27
a - b = 27 : 9
a - b = 3
a + b = 11
a - b = 3
_______ +
a + b + a - b = 11 + 3
2a = 14
a = 7
a + b = 11 => 7 + b = 11 => b = 11 - 7 => b = 4
ab = 74