Solve the equation 5(a – 7) + 11 = 2a – 3(a + 4) for a

5(a – 7) + 11 = 2a – 3(a + 4)

5a - 35 + 11 = 2a - 3a - 12

5a - 24 = -a - 12

add a to both sides

5a - 24 + a = -a -12 + a

simplify

6a - 24 = -12

add 24 to both sides

6a - 24 + 24 = -12 + 24

simplify

6a = 12

divide both sides by 6

6a/6 = 12/6

simplify

a = 2

cost for ordering n tickets online. = 16n+2.50

where n is the number of tickets ordered.

Step-by-step explanation:

Given that when purchasing tickets to a waterpark on internet

he has to pay 16 dollars per ticket and also an additional service cost of 2.50 dollars.

This 2.50 dollars is fixed irrespective of number of tickets he orders

Hence if n tickets are purchased online,

Ticket cost to be paid = 16(n) = 16n

One time service cost            = 2.50

Thus the cost for ordering n tickets online. =total cost

C= 16n+2.50

where C represents the cost, and n is the number of tickets ordered.

Here we substitute n=4, to get his particular  cost

C= 66.50 dollars