Question

Ben has 4 more than twice as many cd's as jake. if they have a total of 31 cd's, home cd's does jake have ?

Answer 1

j = 9 (# of CDs Jake has)

Explanation:

Equations::

b + j = 31 CDs

b = 2j+4

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Substitute for "b" and solve for "j"::

2j+4 + j = 31

3j = 27

j = 9 (# of CDs Jake has)

Answer 2

These are the equations given:
31=B+J
B=2J+4

So you substitute B=2J+4 into 31=B+J

31=2J+4+J

Solve

31-4=3J+4-4
27=3J
27/3=3J/3
9=J

Jake has 9 cd's.