Five books and four pens cost $800. One book costs $120. How much does one pen cost?

5 books + 4 pens= 800$

since one Book=120$

so..

5books=600$

Now, putting the value of books

600$+4pens=800$

4pens= 800$-600$= 200$

one pen= 200$/4= 50$

Hence,

step-by-step explanation:

first, eliminate the parenthesis:

3

x

+

2

−

4

x

second, group like terms:

3

x

−

4

x

+

2

third, combine like terms:

(

3

−

4

)

x

+

2

→

−

1

x

+

2

→

−

x

+

2