Answer:
The answer to 17 is -8. 2+ = 10 - 12 = -2*4 = -8.
The answer to 18 is 28. 4^2 = 16, 7 + 1 = 9 + 3 = 12, 16 + 12 = 28.
Step-by-step explanation:
Answer:

Step-by-step explanation:
From the question, Diana wants her total bill to be less than $50.
Diana pays a fixed monthly bill of
$39 for her mobile phone and an additional
$0.15 per minute for phone internet service.
The bill Diana pays for m minutes of using the internet is $0.15m in a month.
The total monthly bill becomes,

The maximum bill she wants to pay is $50.

This inequality can be solved to determine the number of available minutes.
Answer: 200 adult tickets and 400 student tickets were sold.
Step-by-step explanation:
Let x represent the number of adult tickets that were sold.
Let y represent the number of student tickets that were sold.
Adult tickets to a play cost $1.75 each and student tickets cost $1.25 each. If the income from the play was $850, the expression would be
1.75x + 1.25y = 850- - - - - - - - - -1
Suppose there are twice as many student tickets sold as adult tickets. This is expressed as
y = 2x
Substituting y = 2x into equation 1, it becomes
1.75x + 1.25 × 2x = 850
1.75x + 2.5x = 850
4.25x = 850
x = 850/4.25
x = 200
y = 2x = 2 × 200
y = 400