You’ve made a mistake in your nodal analysis equation. I_2\$I_2\$ is not simply V1/(R1 +R2)\$\frac{V_1}{R_1 +R_2}\$ as it’s not just those two resistors in the circuit. I’ll point out that I_2=V1-V3/R2\$I_2=\frac{V1-V3}{R_2}\$ because this is ohms law. I’ll leave it up to you to determine I_3\$I_3\$ and V_3\$V_3\$.
use some function to modify the representation of math formula