First you had to add by nine from both sides of equation form.
[tex]\frac{1}{4}x-9+9=-15+9[/tex]
Then simplify by equation.
[tex]\frac{1}{4}x=-6[/tex]
Next multiply by four from both sides of equation form.
[tex]4*\frac{1}{4}x=4(-6)[/tex]
Finally simplify by equation.
[tex]x=-24[/tex]
Final answer: [tex]\boxed{x=-24}[/tex]
[tex]6*4=24[/tex]
[tex]4*6=24[/tex]
[tex]24/6=4[/tex]
[tex]24/4=6[/tex]
Hope this helps!
And thank you for posting your question at here on brainly, and have a great day.
-Charlie