Use the equation of -b/2a, so if you have a line you can just plug in the numbers.
Answer:
a. 
b. 
c. 
Step-by-step explanation:
a. 
b. 
c. 
Since 4 nights cost $356, 356÷4=89, so one night costs $89. 7-4=3, so 89×3 is 267. 267+356 is 623. The total cost for 7 nights would be $623
Answer:
x 2 y -4
Step-by-step explanation:
13x = -54 -20y give it is A
-10x = 60 + 20y give it is B
A + B the sum of the left side of equation is equal to the sum of the right side of equation
13 + (-10x) = -54 -20y + 60 + 20y
3x = 60-54
3x = 6
x=2
so put the x value in A or B equation you can receive y value (B is easier)
y = -4
12÷5=1.5 of licorice will each person get