Answer:
The difference in per-mile costs for the two companies is $0.12
Step-by-step explanation:
Gabi sets up the equation 
to find out after how many miles, m, the companies will charge the same amount.
The first company charges 
for m miles driven.
The second company charges 
for m miles driven.
In both these functions, numbers 7.20 and 8,40 represent the initial fee the companies charge.
Numbers 0.22 and 0.1 represent per-mile costs.
Thus, the difference in per-mile costs is 
Another way to solve this problem is to find the cost per mile driven for each company:
1. Cost per-mile 1st company
2. Cost per-mile 2nd company
3. Difference:
First, we can expand the terms on the right side of the equation:
y
−
10
=
2
(
x
−
8
)
y
−
10
=
(
2
×
x
)
−
(
2
×
8
)
y
−
10
=
2
x
−
16
Next, we can add
10
and subtract
2
x
from each side of the equation:
−
2
x
+
y
−
10
+
10
=
−
2
x
+
2
x
−
16
+
10
−
2
x
+
y
−
0
=
0
−
6
−
2
x
+
y
=
−
6
Now, multiply each side of the equation by
−
1
−
1
(
−
2
x
+
y
)
=
−
1
×
−
6
(
−
1
×
−
2
x
)
+
(
−
1
×
y
)
=
6
2
x
+
(
−
y
)
=
6
or
2
x
−
y
=
6
Answer:
x=16.5
Step-by-step explanation:
12.7 + 3.8 = x - 3.8 + 3.8
16.5 = x
Use the distributive property to get 5kj+2k
