Answer:

Step-by-step explanation:
Let
.
and

The graph of the two equations are shown in the attachment.
The points where the two graphs intersected are: 
The x-coordinates of the intersection points are the solutions to
.
Therefore the solutions are: 
1/2 would work for the blank space
because as shown in the image you could relate it to a whole for each one and put it to 100 to figure out what the blank could be
the 0.20 can be converted to 1/5 so that way you can put everything into the 100 group
Answer:
The solutions are
and 
Step-by-step explanation:
we have

Group terms that contain the same variable, and move the constant to the opposite side of the equation

Factor the leading coefficient

Complete the square. Remember to balance the equation by adding the same constants to each side.


Rewrite as perfect squares


square root both sides





A = 6.7 :) hope this helps I double checked
Let numbers of books be 'b' and numbers of CDs be 'c'
We can set up two equations:
Equation [1] ⇒

Equation [2] ⇒

We are solving for the number of books and the number of CDs bought
When we have two equations in terms of two different variables;

and

, that we need to solve, then this becomes a simultaneous equation problem.
First, rearrange Equation [1] to make either

or

the subject:


Then we substitute

into Equation [2]






Now we know the value of

which is

, substitute this value into

we have

Answer:
Numbers of books = 13
Numbers of CDs = 7