Answer
The angle between the vector $\langle8,6\rangle$ and the x axis is $\theta=36.87^\circ$.
Work Step by Step
In order to find the angle between the vector $\langle8,6\rangle$ and the x axis we can simply imagine a triangle with a base of $8$ and a height of $6$. As a result we can find $\theta$ with simple trigonometry.
$\tan{\theta}=\frac{6}{8}=\frac{3}{4}\Rightarrow\theta=\arctan{\frac{3}{4}}\approx36.87^\circ$