Step-by-step explanation:
To find the answer to the expression:
\[
-\frac{13}{4} + \frac{15}{28} + \frac{15}{28} + -\frac{13}{4}
\]
First, we simplify each term:
\[
-\frac{13}{4} + \frac{15}{28} + \frac{15}{28} - \frac{13}{4}
\]
Combine the like terms. Since \(-\frac{13}{4}\) appears twice:
\[
-\frac{13}{4} - \frac{13}{4} = -\frac{26}{4} = -\frac{13}{2}
\]
Next, combine the fractions with denominator \(28\):
\[
\frac{15}{28} + \frac{15}{28} = \frac{30}{28} = \frac{15}{14}
\]
Now, we need to combine \(-\frac{13}{2}\) and \(\frac{15}{14}\). To do this, find a common denominator, which is 14:
\[
-\frac{13}{2} = -\frac{13 \times 7}{2 \times 7} = -\frac{91}{14}
\]
So, we add \(-\frac{91}{14}\) and \(\frac{15}{14}\):
\[
-\frac{91}{14} + \frac{15}{14} = \frac{-91 + 15}{14} = \frac{-76}{14} = -\frac{38}{7}
\]
Therefore, the answer is:
\[
-\frac{38}{7}
\]
