Kilka równań do rozwiązania: ½x + ⅓y = 18 ½x=⅔y x-150=y+150 ¼x=y x+y=45 x-y=25 x=y+5 x-1=2(y-1)

a) ½x + ⅓y = 18|*2 ½x=⅔y x+2/3y=36 ½x=⅔y x=36-2/3y 1/2(36-2/3y)=2/3y x=36-2/3y 18-2/6y=2/3y x=36-2/3y -2/6y-2/3y=-18 x=36-2/3y -y=-18|:(-1) x=36-2/3y y=18 x=36-2/3*18 y=18 x=24 y=18 b) x-150=y+150 ¼x=y x-y=300 1/4x=y -y=300-x|:(-1) 1/4x=y y=-300+x 1/4x=-300+x y=-300+x 1/4x-x=-300 y=-300+x -3/4x=-300|:(-3/4) y=-300+x x=400 y=-300+400 x=400 y=100 x=400 c) x+y=45 x-y=25 2x=70|:2 x=35 35+y=45 y=45-35 y=10 x=35 y=10 d) x=y+5 x-1=2(y-1) x=y+5 x-1=2y-2 x=y+5 y+5-1=2y-2 x=y+5 y-2y=-2-5+1 x=y+5 -y=-6|:(-1) x=y+5 y=6 x=6+5 y=6 x=11 y=6