Erin has quarters and nickels for a total of 16 coins. The value of his coins is $2.60. Let represent the number of quarters and y represent the number of nickels

Note: Consider we need to find each type of coins he has.

Given:

Erin has quarters and nickels for a total of 16 coins.

The value of his coins is $2.60.

To find:

The number of each type of coins.

Solution:

Let x represent the number of quarters and y represent the number of nickels.

According to the question,

Total coins :        ...(i)

Total value :        ...(ii)

Multiply equation (i) by 0.25 and subtract the result from (ii).

Divide both sides by -0.20.

Put y=7 in (i).

Therefore, the number of quarters is 9 and number of nickels is 7.

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below:

answer: the proof is mentioned below.

step-by-step explanation:

since, given:   lines bc = ef

prove:   lines ac > ef

          statements                                           reason

1. bc=ef                                           1. given

2. ac= ab+bc                                 2. because b is the point between the  

                                                            line segment ac

3.   ac > bc                                       3. because if a line segment is equal to

                                                          the sum of two line segments then it is

                                                          always greater then each of these

                                                          individual line segments

4. ac > ef                                         4. by equality property.