I am fuzzy on the process for the following question. If I could get a walk through on the solution process I would be very appreciative. The soln manual only gives the answers. Field and Wave Electromagnetics by Cheng p2-17
A field is expressed in spherical coordinates by $\mathbf{E} = \frac{25}{R^2}\hat{R}$
Find $|\mathbf{E}|$ and $\mathbf{E_x}$ at the point $P(-3,4,-5)$
Thanks in advance.