For this case we have to:
x: It is the variable that represents the number of compact discs.
The cost function must be found considering that each disk costs $7.13. So:

Thus, to find the total cost of "x" compact discs (in $) we substitute the number of discs in the cost function.
Answer:


Euclid's division lemma : Let a and b are two positive integers. There exist unique integers q and r such that
a = bq + r, 0
r < b
Or We can write it as,
Dividend = Divisor × Quotient + Remainder
<u>Work</u><u> </u><u>out</u><u>:</u>
Given integers are 240 and 228. Clearly 240 > 228. Applying Euclid's division lemma to 240 and 228,
⇛ 240 = 228 × 1 + 12
Since, the remainder 12 ≠ 0. So, we apply the division dilemma to the division 228 and remainder 12,
⇛ 228 = 12 × 19 + 0
The remainder at this stage is 0. So, the divider at this stage or the remainder at the previous age i.e 12

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Sam was at the mall for about 4 hours 25 minutes
(ab + 174)/3 <115
multiply by 3 on each side
ab + 174 < 345
subtract 174 from each side
ab < 171
248+ ab >366
subtract 248 from each side
ab> 118
Answer 118< ab < 171