Using a system of equation, we have that:
a)
- x, which is the cost of on-site service.
- y, which is the cost of at-store service.
- z, which is the cost of by-mail service.
b)
The system is:



c)
The cost of one on-site repair service is of $90.
Item a:
The variables are:
- x, which is the cost of on-site service.
- y, which is the cost of at-store service.
- z, which is the cost of by-mail service.
Item b:
On-site service costs <u>3 times as much as at-store service</u>, thus:

By mail service costs <u>$10 less than at-store</u> service, thus:

Last week, the shop completed <u>15 services on-site, 40 services at-store, and 5 services by mail for total sales of $3100</u>, thus:

The system is:



Item c:
- The cost of one on-site repair service is x.
- First, replacing the first two equations into the third, we find y, and then with it we find x.






Then

The cost of one on-site repair service is of $90.
A similar problem is given at brainly.com/question/24823220
$9.47
I just multiplied the total by the refund percentage to get that number. It’s just like finding a tip.
Answer:
6.21 times more
Step-by-step explanation:
Assuming 2.04 x 10^11 was only a typo
you would need to first equal the powers of 10
so 20.4 x 10^10 and 3.28 x 10^10
now that they have the same powers

if it's asking for how many times i would approximate it to 6.21 times more
She should use 13 factors.
All 13 factors are the same thing . . . 7 .
7^13 should be written as 7¹³ .
It means: 7·7·7 · 7·7·7 · 7·7·7 · 7·7·7 · 7
That would be the commutative property