Step-by-step explanation and answers:
a) y=3x+1
y=3*(-1)+1= -3+1= -2
y=3*0+1=0+1=1
y=3*1+1=3+1=4
b) y= -3x+1
y= -3*(-1)+1=3+1=4
y= -3*0+1=0+1=1
y= -3*1+1= -3+1= -2
