Answers; 1.x+y=4 x-y=16 Minus eq 1 frm 2 -2y=12. y=6 Substitute y=6 in eq 1 x=-2. 2. Minus eq 2 frm 1 6y=12 y=2.Substitute y=2 in eq 1 x=-3 3.Minus eq 2 frm 1 -9y=18 y=18/-9 y=-2 Substitute y=-2 in eq 1 x=-3 4..add eq 1 and 2 no answer 5.minus eq 2 frm 1 2y=-6 y=-3.Substitute y=-3 in d equation x=1/2 6.add eq 1 and 2 -x=3 x=-3 substitute it in eq 1 y=-1 7.Multiply eq 1 by 2 and eq 2 by 1 Subtract eq 1 frm 2 .2x=-26 x=-13 8.multiply eq1 by 1 and eq 2 by 4.Subtract eq 1 frm 2 4y=-40 y=-10 Substitute y=-10 in eq 1 x=-20 9. Multiply eq 1 by 2 and eq 2 by1 Add the 2 eqs 3x=12 x=4 Substitute x=4 in eq 1 y=6 This is where I can stop