The problem presents two equations with unknown operations represented by 'D', 'E', and 'F'. We need to find the pattern to solve the third expression.
Let's test arithmetic operations. We observe that if 'D' represents addition (+), 'E' represents subtraction (-), and 'F' represents division (/), the equations hold true, following the standard order of operations (Division first, then Addition/Subtraction).
For Equation 1:
We apply the proposed operations: $37 + 18 - 84 \div 21$
This matches the given result.
For Equation 2:
We apply the same operations: $57 + 28 - 90 \div 15$
This also matches the given result. The pattern is confirmed.
Now, we apply the identified pattern (Number1 + Number2 - Number3 / Number4) to the target expression: 14 D 17 E 8 F 4.
Expression: $14 + 17 - 8 \div 4$
Therefore, the value of the expression is 29.