Answer:
5 + 52.25x
Step-by-step explanation:
flat rate plus cost per pound times number of pounds
5 + 52.25x
-2x+1/2y=18
xint is where y=0
-2x+0=18
-2x=18
divde by -2
x=-9
xint isi (-9,0)
The way i did that in middle school was plot the points then find the slpoe and work it out from there
Expand the left hand side:

Simplify the left hand side:

Subtract 79.99 from both side:

Divide both sides by 17:

So, he must invite less than 7 friend to the party.