The library sells 376 books at its annual used-book fundraiser. they take in a total of $2120. childrens books cost $4, and adults books cost $7. how many childrens books did they sell?
let c = number of childrens books sold, and let a = the number of adult books sold.
which system of equations can the librarians use to solve this problem?
a. 4c+7a = 376
c+a = 2120
a= 376-c
b. 7c+4a = 2120
a+c = 376
c. 4a+7c=2120
c+a = 376
d. 4c + 7a = 2120

1.true 2.false? ? i think. .

step-by-step explanation:

d, x=8

step-by-step explanation:

simplifying

4x + -5 = 2x + 11

reorder the terms:

-5 + 4x = 2x + 11

reorder the terms:

-5 + 4x = 11 + 2x

solving

-5 + 4x = 11 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-5 + 4x + -2x = 11 + 2x + -2x

combine like terms: 4x + -2x = 2x

-5 + 2x = 11 + 2x + -2x

combine like terms: 2x + -2x = 0

-5 + 2x = 11 + 0

-5 + 2x = 11

add '5' to each side of the equation.

-5 + 5 + 2x = 11 + 5

combine like terms: -5 + 5 = 0

0 + 2x = 11 + 5

2x = 11 + 5

combine like terms: 11 + 5 = 16

2x = 16

divide each side by '2'.