construct proofs (in the same fashion that was demonstrated in the video lectures)
to show that the following sequents are valid.
1. (–q --> –p), p ⊢ q
2. (p --> (m --> r), m ⊢ p--> r
3. w--> (s--> (b--> r)) ⊢b--> (w--> (s--> r))
4. –t--> –r ⊢ r--> t

c

step-by-step explanation:

at least i think its

solve systems of equations by graphing. a system of linear equations contains two or more equations e.g. y=0.5x+2 and y=x-2. the solution of such a system is the ordered pair that is a solution to both equations. to solve a system of linear equations graphically we graph both equations in the same coordinate system