To solve this expression, we need to follow the order of operations (PEMDAS/BODMAS).

First, let's simplify the expression inside the parentheses:
(0,4:2 1 phan 2) = (0.4 ÷ 2) + (1 ÷ 2) = 0.2 + 0.5 = 0.7

Next, let's simplify the expression inside the second parentheses:
(4,2-1 3 phan 40) = (4.2 - 1) ÷ 40 = 3.2 ÷ 40 = 0.08

Now, let's substitute the simplified values back into the original expression:
1 7 phan 20 : 2,7 ; 1,35 + (0,4:2 1 phan 2) X (4,2-1 3 phan 40)
= 1 7 phan 20 ÷ 2,7 ; 1,35 + (0.7) X (0.08)

Next, let's perform the multiplication:
(0.7) X (0.08) = 0.056

Now, let's substitute the multiplication result back into the expression:
1 7 phan 20 ÷ 2,7 ; 1,35 + 0.056

Next, let's perform the division:
1 7 phan 20 ÷ 2,7 = 1.7 ÷ 2.7 = 0.6296

Now, let's substitute the division result back into the expression:
0.6296 ; 1,35 + 0.056

Finally, let's perform the addition:
0.6296 + 1.35 + 0.056 = 2.0356

Therefore, the final result of the expression is 2.0356.