<em><u>Answer:</u></em>
f(x) = 4x + 18; 18 ≤ y ≤ 30
<u><em>Step-by-step explanation:</em></u>
It would be that because if they want to increase by 4 customers every week you would attached that to x and since they started out with 18 customers they add 18 to the total weeks.
So you must set this up as a system of equations
n= noble fir trees
d= douglas fir trees
5n + 3d = $420
12n + 9d = $1,080
To get a positive output you have to multiply the second equation by 3 to be able to be divisable to one another
36n + 18d = 3,240
now divide the equation by 18
2n + d = 180
-2n -2n
d = 180 - 2n
Now put that equation in the first as d ^^^
5n + 3(180 -2n) = 420
5n + 540- 6n = 420
- 540 -540
1n = 120
n = 120
Now put n into the second equation( none changed one) to find d
12(120) + 9d = 3240
1440 + 9d = 3240
-1440 -1440
9d = 1800
÷9 ÷9
d= 200
so the noble is $ 120
and the douglas is $200
X is equal to a negative one point 5
Answer: Both numbers 6/5 and 3/2 do not have a common denominator. Just as how 2 cannot go into 5 evenly.
That's really hard homework I really have never seen anything like that but I'll ask my sister.