Answer:
1
Step-by-step explanation:
-f + 2 + 4f = 8 - 3
3f = 6 - 3
3f = 3
f = 1
Answer:
0.75=10x
Step-by-step explanation:
Answer:
492.99
Step-by-step explanation: x = amount invested at 12%
y = amount invested at 9%
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x + y = 20287
0.12x = 0.09y + 492.99
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put the system of linear equations into standard form
---
x + y = 20287
0.12x - 0.09y = 492.99
The numbers of new CDs is 30 and the old CDs is 21.
To solve this problem, we have to write a system of equations in which we would know the numbers of each types of CD she bought.
<h3>System of Equations</h3>
This is used to solve a series or complex of word problems in which we can represent in a mathematical statements;
- Let n represents numbers of new CDs
- Let u represents numbers of old CDs
The equations can be represented as

Let's take equation (i)
Making n the subject of formula

we can put equation (iii) into equation (ii)

Let's put the value of u into equation (i)

From the calculations above, the numbers of new CDs is 30 and the old CDs is 21.
Learn more on system of equations here;
brainly.com/question/13729904