How do I isolate the āIā variable

Answer:
[tex] I = \pm \sqrt{\dfrac{P}{R}} [/tex]
Step-by-step explanation:
[tex] P = I^2R [/tex]
Divide both sides by R.
[tex] \dfrac{P}{R} = I^2 [/tex]
Switch sides.
[tex] I^2 = \dfrac{P}{R} [/tex]
Take the square root of both sides.
[tex] I = \pm \sqrt{\dfrac{P}{R}} [/tex]