Which of the assignments of truth values for Na, Ra, and Va shows the following proof invalid?
1)(x)(Nx ? Rx) $\quad $ Na ? Ra
2.(x)(Vx ? Nx) $\quad $Va ? Na
3.? (x)(Rx ? Vx) $\quad $Ra ? Va

A)Na Ra Va - TTF
B)Na Ra Va - TFT
C)Na Ra Va - FFT
D)Na Ra Va - FTT

Question

Which of the assignments of truth values for Na, Ra, and Va shows the following proof invalid?
1)(x)(Nx ? Rx) $\quad $ Na ? Ra 
2.(x)(Vx ? Nx)  $\quad $Va ? Na 
3.? (x)(Rx ? Vx)  $\quad $Ra ? Va

A)Na Ra Va - TTF
B)Na Ra Va - TFT
C)Na Ra Va - FFT
D)Na Ra Va - FTT

Quizplus · Accepted Answer

The Answer is A

Which of the Assignments of Truth Values for Na, Ra \quad

Which of the Assignments of Truth Values for Na, Ra $\quad$