(Solving rational expressions) 12/x = 48/x+9

Question

Solve the rational expression

 

12 = 48

x   = x+9

Answer 1

12/x=48/(x+9)

you can cross multiply

48x=12(x+9)

48x=12x+108

48x-12x=108

36x=108

x=108/36

x=3

a simpler way of doing the problem...

12     48

__ = ___

 x     (x+9)

 

use equal fractions

multiply 12 by 4 to get 48 and multiply x by 4 to get (x+9)

4x=x+9

4x-x=9

3x=9

x=9/3

x=3 again