For a certain interaction, the potential energy in joules is given by \(U(x)=a x+b x^{2}\), where \(a=+4.0 \mathrm{~J} / \mathrm{m}\) and \(b=-2.0 \mathrm{~J} / \mathrm{m}^{2}\). If, at some instant, a \(10-\mathrm{kg}\) object taking part in this interaction has an \(x\) component of velocity of \(-3.0 \mathrm{~m} / \mathrm{s}\) and a position \(x=+2.0 \mathrm{~m}\), and moves in one dimension only. What is its speed

(a) at \(x=+1.0 \mathrm{~m}\) and 

\((b)\) at \(x=-1.0 \mathrm{~m}\) ?