Answer:
[tex]\Huge \boxed{2x-3=-21}[/tex]
Step-by-step explanation:
Let the number be x.
The difference of two values is the result from subtracting them.
[tex]2x-3=-21[/tex]
Add 3 to both sides.
[tex]2x=-18[/tex]
Divide both sides by 2.
[tex]x=-9[/tex]
The number is -9.