Question about a Flip Flop circuit

[Salman Ali]

Hello! I am confused in a question I found on youtube. I have uploaded the screen shots.
He told that with respect to S and R we have to write the change from Q to Q+( next state). But I am not getting it. How he wrote Q+ states?Is he considering that when S=1 , we have to set the circuit i.e on Q , 1 will be stored and the circuit will be set and vice versa? But this is a nand latch right? S is above R and infront of S there is Q. So it is a nand latch in which when S=1 Q is 0 . Thanks

 

[Baluncore]

When the F/F is clocked the state of S and R are copied through to Q and Qbar respectively.
If x is different to Q then the next state will be 1, which is the XOR function.
Answer (c); Q+ = x XOR Q.