Answer:
[tex]x = -10.5[/tex]
Step-by-step explanation:
Represent the number as x
Difference of the number and x:
[tex]x - 9[/tex] --- (1)
Sum of 3 times the number and 12:
[tex]3 * x + 12\\[/tex] ---- (2)
Equate 1 and 2
[tex]x - 9 = 3 * x + 12[/tex]
[tex]x - 9 = 3x + 12[/tex]
Collect Like Terms
[tex]x - 3x = 9 + 12[/tex]
[tex]-2x = 21[/tex]
Make x the subject
[tex]x = -\frac{21}{2}[/tex]
[tex]x = -10.5[/tex]
