using the relationship between the zeroes of the quadratic polynomial.$$
\begin{aligned}
&\text { Sum of zeroes }=\frac{-\left(\text { coefficient of } x^{2}\right)}{\text { coefficient of } x^{3}} \\
&\Rightarrow a-b+a+a+b=\frac{-(-6)}{2} \\
&\Rightarrow 3 a=3 \\
&\Rightarrow a=1
\end{aligned}
$$
If $(a-b), a$ and $(a+b)$ are zeros of the polynomial $2 x 3-6 x 2+5 x-7$ write the value of a.
If $(a-b), a$ and $(a+b)$ are zeros of the polynomial $2 x 3-6 x 2+5 x-7$ write the value of a.