If the angle between and is acute and the angle between and the x-axis lies between and . Find the…

If the angle between $\vec{a} = -3\hat{i} + x\hat{j} + \hat{k}$ and $\vec{b} = x\hat{i} + 2x\hat{j} + \hat{k}$ is acute and the angle between $\vec{b}$ and the x-axis lies between $\frac{\pi}{2}$ and $\pi$. Find the range of values for $x$.