a) 7x-11y=22/(-2) 2x+3y=18/(-7) -14x++22y=-44 -14x-21y=-126 _________________________+ y=170 b) 2x+3y=4/(-5) 5x+6y=7/(2) -10x-15y=-20 10x+12y=14 ___________________+ -3y=-6/(-3) y=2 2x+3 x 2=4 2x+6=4 2x=2/2 x=1 y=2 x=1 c) 3x+y=-1 -3y-5y=-7 ____________________+ -4y=-8/4 y=2 3x + 2 =-1 y=2 y=2 x=1
a) 7x-11y=22 2x+3y=18 2x=18-3y //2 7x-11y=22 x=9-3/2y 7(9-3/2y)-11y=22 x=9-3/2y 63-21/2y-11y=22 x=9-3/2y -21 1/2y=22-63 //-21 1/2 x=9-3/2y y=82/43 x=9-3/2*82/43 y=82/43 x=9-123/43 y=82/43 x=6 6/43 y=82/43 b) 2x+3y=4 5x+6y=7 2x=4-3y 5x+6y=7 x=2-3/2y 5(2-3/2y)+6y=7 x=2-3/2y 10-15/2y+6y=7 x=2-3/2y -3/2y=7-10 //-3/2 x=2-3/2y y=2 x=2-3/2*2 y=2 x=-6 y=2 c) 3x+y=-1 -3x-5y=-7 ____________ -4y=-8//-4 y=2 3x+y=-1 3x+2=-1 3x=-3//3 x=-1 y=2 x=-1
