A number added to one third of itself equals 12 . what is the number​

9

Step-by-step explanation:

x+1/3x=12

(3x+1x)/3=12

4x/3=12

4x=12×3

4x=36

x=36/4

x=9

1/3+x=12(cross multiply)

x+1=12*3

x+1=36(collect like terms)

x=36-1

x=35

the answer to this would be 5x^3-6x^2-24 over 3x^2

hope this if needed hmu