Let y=total cost
We have 4 friends that paid an extra $6 each and 4 friends that paid regular admission.
Friends that paid extra= 4(x+6)
Friends that paid regular= 4x
Now we need to add those together.
y= 4(x+6) + 4x
Distribute the 4
y= (4*x) + (4*6) +4x
y=4x + 24 +4x
y=8x + 24
Hope this helps!! :)