The library sells 376 books at its annual used-book sale. the sale takes in a total of $2119. children's books cost $4, and adult books cost $7. let x = number of children's books sold, and let y = the number of adult books sold. which system of equations can the librarians use to model this situation?

system of equations are

Step-by-step explanation:

Let x = number of children's books sold,

and let y = the number of adult books sold

The library sells 376 books at its annual used-book sale

so, we get equation as

Children's books cost $4

So, total cost of children book is 4x

adult books cost $7

So, total cost of adult book is 7y

so, we get total cost is 4x+7y

he sale takes in a total of $2119

so, we get equation as

so,

system of equations are

i belive those are the ones that are under 90 degreese.

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is