Answer:

Step-by-step explanation:
Given


Required
Eliminate a
Multiply the first equation by -4

Add to the second equation

Solve brackets

Open bracket


At this point, a has been eliminated;
From the list of given options, the option that answers the question is 
Answer:
In khan academy, just plot the points and the answer is yes.
Step-by-step explanation:
Use the table to plot the points and you'll figure out that it's proportional- so the answer to the question below is yes. Doesn't need too much explaining.
Answer:
c
Step-by-step explanation:
He needs to earn ; 77.99-20= 57.99 dollars
so in one week there are 2 weekends; so he earns 6×3×2 = 36 dollars
so no of week = 57.99÷ 36= 1.6 weeks
so weeks are in natural no thus it will take him 2 weeks !!
A. Yes, the value of this function is 8 when x is 15.
B. False. I noted right away that the ordered pair (0,5) is not included, and some of the ordered pairs included do not represent the given function.
C. Yes, f(5) = 6. See (A) above.
D. False. The range of this function is the set of integers between 5 and 13 inclusive.