a) x+2y=-2 *( -2 ) 2x-y=1 ODPOWIEDZ -2x -4y = 4 y = -1 2x -y =1 x = 0 -5y =5 : (-5) y = -1 x - 2 = -2 x = 0
a) x + 2y = -2 2x - y = 1 x= -2 - 2y 2 * (-2-2y) - y =1 x=-2-2y -4-4y-y=1 x=-2-2y -5y=5 /:(-5) x=-2-2y y=-1 x=-2-2*(-1) x=0 y=-1 b) x+4y=-2 3x-8y=10 x=-2-4y 3*(-2-4y) - 8y =10 x=-2-4y -6-12y-8y=10 x=-2-4y -20y=16 /:(-20) x=-2-4y y=-0,8 x=-2-4*(-0,8)= -2+3,2 = 1,2 c) x-2y=3 -2x+y=0 x=3+2y -2*(3+2y) + y=0 x=3+2y -6-4y+y=0 x=3+2y -3y=6 /:(-3) x=3+2y y=-2 x=3+2*(-2) = 3-4= -1 d) 2x+y=9 5x-4y=3 y= 9-2x 5x - 4*(9-2x) = 3 y=9-2x 5x - 36+8x=3 y=9-2x 13x=39 /:13 y= 9-2x x=3 y=9-2*3 = 9-6 = 3 e) 3x-2y=5 2x-y=4 3x-2y=5 -y=4-2x /*(-1) 3x-2y=5 y=-4+2x 3x-2*(-4+2x)=5 y=-4+2x 3x+8-4x=5 y=-4+2x -x=-3 /*(-1) y=-4+2x x=3 y=-4+2*3 = -4+5 = 1 f) 2x+9y=-9 -3x+3y=8 2x=-9-9y /:2 -3x+3y=8 x=-4,5 - 4,5y -3 * (-4,5 - 4,5y) + 3y = 8 x=-4,5 - 4,5y 13,5 + 13,5y +3y=8 x=-4,5 - 4,5y 16,5y = 5,5 /:16,5 x=-4,5 - 4,5y y = 1/3 x= -4 1/2 - 4 1/2 * 1/3 = -4,1/2 - 4 1/6= -4 3/6 - 4 1/6= -8, 4/6
