18/12=22.50/n
he could buy 15 gallons
Answer:
x < -1 or x > 9
Step-by-step explanation:

Add 3 to both sides.

Simplify.

Divide both sides by 10.

Simplify.

Apply absolute value rule: If
then
or 
or 

Add 4 to both sides.

Simplify.


Add 4 to both sides.

Simplify.

Combine the intervals.
or 
Two plus the product of 5 and x
or
the product of 5 and x plus 2
or
5 times x plus two