Hey there!
"15 more than" will mean that 15 will be added to another term. The other term is "half a number", meaning 0.5x, where x is the number. This equation is equal to 9. The final equation is 0.5x + 15 = 9.
To solve this, cancel out the terms until you find what x is equal to:
0.5x + 15 = 9 (subtract 15 from both sides)
0.5x = –6 (divide both sides by 0.5)
x = –12 (final answer)
Hope this helped you out! :-)