An elastic spring under tension of 3 N has a length $a$. Its length is $b$ under tension 2 N. For its length $( 3 a - 2 b )$, the value of tension will be $\_\_\_\_$ N.
An elastic spring under tension of 3 N has a length $a$. Its length is $b$ under tension 2 N. For its length $( 3 a - 2 b )$, the value of tension will be $\_\_\_\_$ N.