Remember that parentheses come first. Follow PEMDAS
Answer:
26 customers
Step-by-step explanation:
Represent customers entering as y and those buying hot dogs as x


Required
Determine the number of people buying hotdogs (x)
Substitute 4x + 9 for y in the second equation

Collect Like Terms


Hello!
I believe the most logical answer is 7⋅10^9
I hope it helps!