Answer: -90
Step-by-step explanation: To solve this equation for y, we need to isolate the variable y on one side of the equation. To do this, we can multiply both sides of the equation by -5 to get rid of the fraction on the right side:
18 = y / -5
18 * -5 = y / -5 * -5
-90 = y
Therefore, the value of y that satisfies the equation is -90.