plz answer...

a root of an equation must satisfy the equation, i.e. after substituting the value of the root in place of the variable, we must get,

 LHS=RHS.

so in this case,

 by substuting,x=2/3

we get,

(4a/9)+(14/3)+b=0

i.e.

4a+42+9b=0...(i)

Simly,

 by substituting x = -3

we get,

9a-21+b=0..(ii)

Solving both you can find a and b.