Various HNC issues

I've only a few questions left on a HNC assignment and am stupmed for one reason.

A voltage given by the expression v = 100sin314t + 50sin942t - 40sin1570t is applied to an impedance of (40 + j30)Ω

What's required
i) An expression for the instantaneous current flowing in the circuit
iii) The effective rms current
iv) The power supplied to the load

Whats thrown me is the 40+j30.. if it was just 40Ω i could do it no problem..

Also

'i) An expression for the instantaneous current flowing in the circuit'

Umm..? What? Aha..

Help would be greatly appreciated. Thanks,
Jon.