Thevenin Equivalent Circuit with Sinusoidal Current Source (Vth)
Looks like you are both correct, although you are more precise. The "7's" in the result 7 + 7j are an approximation of 5*sqrt(2) which somewhat more precisely = 7.07107, so I would prefer the solution given in rectangular form be 7.1 + 7.1j since 7.07.... rounds closer to 7.1 than 7.0