Answer :

Sure, let's solve the expression step-by-step:

[tex]\[ 2.5 - [6.50 - \{2.80 \div 2 \times (7.5 - 5.4 - 3.9)\}] \][/tex]

1. Innermost parentheses calculation
[tex]\[ 7.5 - 5.4 - 3.9 \][/tex]
Compute [tex]\(7.5 - 5.4\)[/tex]:
[tex]\[ 7.5 - 5.4 = 2.1 \][/tex]
Now subtract [tex]\(3.9\)[/tex] from [tex]\(2.1\)[/tex]:
[tex]\[ 2.1 - 3.9 = -1.8 \][/tex]

2. Division inside the braces
[tex]\[ 2.80 \div 2 \][/tex]
Compute:
[tex]\[ 2.80 \div 2 = 1.4 \][/tex]

3. Multiplication inside the braces
[tex]\[ 1.4 \times (-1.8) \][/tex]
Compute:
[tex]\[ 1.4 \times -1.8 = -2.52 \][/tex]

4. Braces calculation
[tex]\[ 6.50 - (-2.52) \][/tex]
Since subtracting a negative is the same as adding the absolute value:
[tex]\[ 6.50 + 2.52 = 9.02 \][/tex]

5. Brackets calculation
[tex]\[ 2.5 - 9.02 \][/tex]
Compute:
[tex]\[ 2.5 - 9.02 = -6.52 \][/tex]

So, the result of the expression is [tex]\(-6.52\)[/tex].