Finding the value of current I
No, it's wrong.

Since the current will divide in parallel connections, there are different currents flowing through the branches those are \$I\$1, \$I\$2 and \$I\$3.

\$I\$ is the whole current supplied by the source. So you need to calculate all the branch currents and then add them.

That means you need to use KCL, \$I\$ = \$I\$1 + \$I\$2 + \$I\$3.