So we'll assume the number is x.
So,
15+[tex]\frac{x}{2}[/tex]= 9.
Now, we solve for x:
[tex]\frac{x}{2}[/tex]= 9-15
[tex]\frac{x}{2}[/tex]= -6
x = -6*2
x = -12
Check work:
15+[tex]\frac{-12}{2}[/tex]= 9
15+(-6) = 9
15-6 = 9
9 = 9
