$\begin{aligned} \stackrel{m}{E} & =E_1+E_2 \\ \stackrel{E}{E}_1 & =\frac{1}{4 \pi \varepsilon_0} \times \frac{\sqrt{10} \times 10^6}{10} \times\left[\frac{-\hat{i}+3 \hat{j}}{\sqrt{10}}\right] \\ \stackrel{E}{E}_2 & =\frac{1}{4 \pi \varepsilon_0} \times \frac{\left(-25 \times 10^{-6}\right)}{25} \times\left[\frac{-4 \hat{i}+3 j}{5}\right] \\ \stackrel{E}{E}_2 & =9 \times 10^9\left[\frac{-\hat{i}+3 \hat{j}}{10}-\left(\frac{-4 \hat{i}+3 \hat{j}}{5}\right)\right] \\ & =\frac{9 \times 10^3}{10}[-\hat{i}+3 \hat{j}+8 \hat{i}-6 \hat{j}] \\ & =9 \times 10^2[+7 \hat{i}-3 \hat{j}] \\ & =(63 \hat{j}-27 \hat{j}) \times 10^2\end{aligned}$