a) (x+y)/2 - (x-y)/4= -1 |*4 x+y=2 2(x+y)-(x-y)=-4 x+y=2 2x+2y-x+y=-4 x+y=2 x+3y=-4 x+y=2 |*(-1) x+3y=-4 -x-y=-2 _______________ 2y=-6 y=-3 x+3 * (-3) =-4 x-9=-4 x=5 x=5 y=-3 b) 2(x-1)+3 (y-2) =5 3(x+y) -2 (x-2) =7 2x-2+3y -6 =5 3x +3y -2x +4 =7 2x+3y -8=5 x+3y +4=7 2x+3y=13 x+3y =3 |*(-1) 2x+3y=13 -x-3y=-3 ________________ x=10 10+3y=3 3y=-7 y=-2⅓ x=10 y=-2⅓
a) (x+y)/2 - (x-y)/4= -1 |*4 x+y=2 2x+2y-x+y=-4 x+y=2 x+3y=-4 y=2-x x=-4-3(2-x) x=-4-6+3x x-3x=-10 -2x=-10 x=5 y=2-x y=2-5 y=-3 x=5 y=-3 b) 2(x-1)+3 (y-2) =5 3(x+y) -2 (x-2) =7 2x-2+3y -6 =5 3x +3y -2x +4 =7 2x+3y -8=5 x+3y +4=7 2x+3y=13 x+3y =3 2x+3y=13 x=3-3y 2(3-3y)+3y=13 6-6y+3y=13 -3y=13-6 -3y=7 y=-7/3 x=3-3y x=3-3(-7/3) x=3+7 x=10 x=10 y=-2⅓
1. (x +y)/2 -(x -y)/4 = -1 I*4 x +y =2 2(x +y) -(x -y) = -4 x +y =2 2x +2y -x +y = -4 x +y = 2 x +3y = -4 x +y = 2 I*(-3) x +3y = -4 -3x -3y = -6 ---------------- -2x =-10/:(-2) x =5 x +y =2 y = 2 -x y = 2 -5 y = -3 x =5 y = -3 2. 2(x-1) +3(y -2) =5 3(x +y) -2(x -2) =7 2x -2 +3y -6 =5 3x +3y -2x +4 =7 2x +3y =13 x +3y = 3 I*(-1) 2x +3y =13 -x -3y = -3 ------------------ x =10 3y = 3-x 3y =3 -10 3y = -7 y = -7/3 y = -2 1/3 x =10 y = -2 i1/3
