a= 6-2b-3c
then put that equation inside the first one and then the second one
you get -6*(6-2b-3c)+2b-3c=23
and 5*(6-2b-3c)+4b-3c=-12
14b-15c=59
14b-18c=18/*(-1)
--------------------
3b=41
Answer: 1 is not a perfect square. 3 is the only prime number one less than a square.
5 divided by -5 is -1 hope this helps
Missing questions and subsequent solutions:
(a) Write an equation for company A for cost, C, number of months, n, that Beni will pay for the phone.
Solution:
For company A:
C = 72.25 + 85.50n
(b) Write an eqyation for company B for cost, C, and number of months, n, that Bei will pay for the phone.
Solution:
For company B:
C = 151.25 + 65.75n
(c) Write an inequality when the cost from company A is better than cost from company B.
Solution:
72.25 + 85.50n ≤ 151.25 + 65.75n
(85.50-65.75)n ≤ (151.25 - 72.25)
19.75 n ≤ 79
n ≤ 4
(d) Value of n for which cost from the two companies will be the same.
Solution:
If cost for companies A and B are the same, then
72.25 + 85.50n = 151.25 + 65.75n
(85.5 - 65.75)n = 151.25 - 72.25
19.75n = 79
n = 79/19.75 = 4 months
After 4 months,
C = 72.25 + 85.5*4 = $414.25
