i know how to solve this but i don’t understand what it means by “what is x if g(x) is 150”??

Answer:
Step-by-step explanation:
The rule is 5x - 15
g(x) = 150 which is the same thing as saying
y = 5x - 15
y = 150
150 = 5x - 15 Add 15 to both sides
165 = 5x Divide by 5
35 = x
Remember that g(x) has all the properties of y