Question 1195906
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x = cost of the textbook
4x = four times the cost of the textbook
4x+20 = twenty more dollars added to the previous amount
4x+20 = cost of the calculator


The textbook costs x dollars.
The calculator costs 4x+20 dollars.
These two items add to a total cost of $160 before tax.


textbook + calculator = total
(x) + (4x+20) = 160
5x+20 = 160
5x = 160-20
5x = 140
x = 140/5
x = 28
The textbook costs $28


4x+20 = 4*28+20 = 112+20 = 132
The calculator costs $132


The total cost is 28+132 = 160 to confirm our answers.


<font color=red>Answers:
textbook = $28
calculator = $132</font>


Side note: Desmos and GeoGebra are free online calculators that have far more features than anything a TI83 or TI84 can do. Also, they are much faster. The only drawback is that in formal test environments (eg: SATs), such online calculators are not allowed. 
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