687*38-25*71*2²+313*38

To solve the expression \( 687 \times 38 - 25 \times 71 \times 2^2 + 313 \times 38 \), we will begin by calculating each term step by step.

1. Calculate \( 687 \times 38 \): \[ 687 \times 38 = 26094 \]

2. Calculate \( 2^2 \): \[ 2^2 = 4 \]

3. Calculate \( 25 \times 71 \times 4 \): \[ 25 \times 71 = 1775 \] \[ 1775 \times 4 = 7100 \]

4. Calculate \( 313 \times 38 \): \[ 313 \times 38 = 11994 \]

Now we can substitute these values back into the original expression:

\[ 26094 - 7100 + 11994 \]

5. Perform the subtraction and addition: \[ 26094 - 7100 = 18994 \] \[ 18994 + 11994 = 30988 \]

Thus, the final result of the expression \( 687 \times 38 - 25 \times 71 \times 2^2 + 313 \times 38 \) is: \[ \boxed{30988} \]