Rewrite each equation for y in terms of x

x-3y= -4

6x+3y=1

express Y in terms of X

x-3y =-4

so x=-4 +3y

so x +4 = 3y

therefor (x+4)/3 = y

For the second one,

3y = 1-6x

so y = (1-6x)/3

Happy studies.