How do you solve 8/12=r/(r+1)?

2 Answers
Sep 15, 2016

Cross multiply, then solve as usual.

Explanation:

Cross multiply.

8(r+1)=12r

Expand the left-hand side.

8r+8=12r

Subract 8r from both sides.

8=12r-8r

Simplify.

8=4r

Divide both sides by 4.

8/4=r

Simplify.

2=r

Switch sides.

r=2

Sep 15, 2016

r=2

Explanation:

8/12=r/(r+1)
=> 2/3=r/(r+1)

=>3r=2(r+1)
=> 3r=2r+2
=> r=2