Answer:
1) When x is 1, y is 4, and vice versa
2) When x is -6, y is 42, and when x is 7, y is 114
3) When x is -2, y is 2, and when x is 8, y is 42
Step-by-step explanation:
1)

which can be rearranged as
.
Substituting this lone y into the first equation, you get:

Move everything to one side:

Factor:



2)
which can be rearranged as
.

Let's use elimination this time and subtract the first equation from the second:

Factor:



3)


Let's set the two equations equal to each other through substitution:

Move everything to one side:

Factor:



Hope this helps!
Answer:
C. 244
Step-by-step explanation:
It costs 79 dollars a month = 79x
It costs 0.15 dollars for every text message over 1000 = 0.15y
The equation is:
79x + 0.15y = z
X = months
Y = Each text message over 1000
Z = the total amount spent
Let's plug in our values
79(1) + 0.15(1100) = z
79 * 1 = 79
0.15 * 1100 = 165
79 + 165 = z
79 + 165 = 244
z = 244
C. 244
Answer:
D
Step-by-step explanation:
Yes. Slope = rise over run so you go up one, over five