Answer:
-7.75
Step-by-step explanation:
[tex]\text{if}\ x = 8 \rightarrow y = 124\\y \propto x\\y = kx\\\\124 = k \times 8 = 8k\\\frac{124}{8} = \frac{8k}{8}\\15.5 = k\\\\\text{We've now found the formula}\\y \propto x\\y = kx = 15.5x\\\\x = -\frac{1}{2} \rightarrow y = ?\\y = 15.5x = 15.5 \times -\frac{1}{2} = -7.75[/tex]