BY SUBSTITUTION :
equation 1 : x-3y=1 ; x=1+3y
equation 2 : 2x+3y=-4
1 -> 2 : 2(1+3y)+3y=-4
2+6y+3y=-4
9y=-6
y=-2/3
x=1+3(-2/3) = 1-2 = -1
(-1,-2/3)
BY ELIMINATION :
multiply the first equation by 2 which results to 2x-6y=2 then subtract it to equation 2 to get 0x-9y=6 solve for y; y=-2/3 then substitute y to equation 1 to get x=-1
