Objective To use tables to compare linear expressions.

1
Objective- To use tables to compare linear
expressions.
Acme Copiers charges 250 per month and one cent
per copy. Best Printers charges 70 per month
and three cents per copy. When is Acme cheaper?
Let n the number of copies
Let C the total charge
Acme
Best
C 250 .01n
C 70 .03n
2
Let n number copies
Let C total charge
Acme
Best
C 250 .01n
C 70 .03n
n
Acme Charge
Best Charge
250 .01( 0 ) 250
70 .03( 0 ) 70
0
2,000
250 .01(2,000) 270
70 .03(2,000) 130
4,000
250 .01(4,000) 290
70 .03(4,000) 190
6,000
250 .01(6,000) 310
70 .03(6,000) 250
8,000
330
310
10,000
350
370
12,000
370
430
14,000
390
490
410
550
16,000
18,000
430
610
3
Let n number copies
Let C total charge
Acme
Best
C 250 .01n
C 70 .03n
n
Acme Charge
Best Charge
250 .01( 0 ) 250
70 .03( 0 ) 70
0
2,000
250 .01(2,000) 270
70 .03(2,000) 130
4,000
250 .01(4,000) 290
70 .03(4,000) 190
6,000
250 .01(6,000) 310
70 .03(6,000) 250
8,000
330
310
10,000
350
370
Best is cheaper at 8,000 copies, but Acme is
cheaper at 10,000 copies.
4
Let n number copies
Let C total charge
Acme
Best
C 250 .01n
C 70 .03n
n
Acme Charge
Best Charge
8,000
250 .01(8,000) 330
70 .03(8,000) 310
8,500
250 .01(8,500) 335
70 .03(8,500) 325
9,000
250 .01(9,000) 340
70 .03(9,000) 340
9,500
250 .01(9,500) 345
70 .03(9,500) 355
10,000
350
370
Acme is cheaper at 9,000 copies or more.
5
A Better Way !
Let n number copies
Let C total charge
Acme
Best
C 250 .01n
C 70 .03n
When do they cost the same?
250 .01n 70 .03n
- .01n - .01n
250 70 .02n
They cost the same at 9000 copies.
180 .02n
.02 .02
9000 n