a) x=-y x-y=6 x=-y -y-y=6 x=-y 2y=6 /:(-2) x=-y y=-3 x=3 y=-3 b) y=x+3 2x+y=9 y=x+3 2x+x+3=9 y=x+3 3x=9-3 y=x+3 3x=6 /:3 y=x+3 x=2 x=2 y=5 c) x-4y=15 y=4x x-4*4x=15 y=4x y=4x x-16x=15 y=4x -15x=15 /(-15) x=-1 y=-4 d) y=-2x-1 x=y+7 x=y+7 y=-2(y+7)-1 x=y+7 y=-2y-14-1 x=y+7 y+2y=-15 x=y+7 3y=-15 /:3 y=-5 x=2 e) -3x=2y y=1-x y=1-x -3x=2(1-x) y=1-x -3x=2-2x y=1-x -3x+2x=2 y=1-x -x=2 x=-2 y=3 f) {5x-2y=0 {7x+4y=0 -2y=-5x(-1) [ wyznaczyliśmy y] {7x+4y=0 2y=5x 7x + 10x=0 x=0 y=0 g) x+3y=3 x-y=1 /+y x+3y=3 x=1-y 1-y+3y=3 /-1 x=1-y -y+3y=2 x=1-y 2y=2 /:2 x=1-y y=1 x=1-1 y=1 x=0 h) 3m-n=9 /-3m 2m-5n= -11 -n=9-3m /× -1 2m-5n= -11 n=-9 - (-3)m 2m-5n=-11 2m-5(-9-(-3)m)=-11 n=-9 - (-3)m 2m- (-45) - (-15)m = -11 /+(-45) n=-9 - (-3)m 2m - (-15)m = - 11 +(-45) n=-9 - (-3)m 17 m = -56 i) 5x=4-2y 4x=y=3 5x=4 - 2(4x) 4x=y=3 5x=4-8x /+8x 4x=y=3 13x=4 /÷13 4x=y=3 x=4/13 j)x+3y=3 x-y=5 x+3y=3 x=5+y 5+y-3y=3 x=5+y -2y=-2 x=5+y y=1 x=5+1 y=1 x=6 Mam nadzieje że pomogłam , liczę na naj ;-)
