9,6^2+18,8^2=X^2
92,16+353,44=X^2
X^2=445,6
X=21
Total money Marcus has = $28
Money spent to buy a notebook = $3.75
Money left now = 
Money needed to be saved = $11.25
So, the amount of money Marcus can spend = 
Cost of a packet of chips = $1.30
The inequality to determine the maximum number of chips he can buy is:
Let the number of chips Marcus can buy = x
As he cannot spend more than $13 to buy chips so equation becomes:

Solving this we get

Hence, Marcus can buy a maximum of 10 packs of chips and save $11.25
Answer:
y=-5x+7
Step-by-step explanation:
Prallel lines have the same slope
so the slope of the unknown line is -5
and passes through(1,2)
y-2=-5(x-1)
slope-intercept form:y=-5x+7
Answer:
Median is 18, because 18 is the middle number.
Step-by-step explanation: