a) x+3y=3 x-y=5 x=3-3y 3-3y-y=5 x=3-3y -4y=5-3 x=3-3y -4y=2/:(-4) x=3-3y y=2/4 y=2/4 [w ułamku] x=3-3*2/4 y=2/4 x=3-2 2/4 y=2/4 x=2/4 b) 2x-y=10 x+5y=-17 2x-10=y x+5*(2x-10)=-17 2x-10=y x+10x-50=-17 2x-10=y 11x=-17+50 2x-10=y 11x=33/11 x=3 2*3-10=y x=3 y=-4 d) 4a-2=b 3a+7b=1,5 b=4a-2 3a+7*(4a-2)=1,5 b=4a-2 3a+28a-14=1,5 b=4a-2 31a=1,5+14 b=4a-2 31a=15,5/31 b=4a-2 a=15,5/31 [w ułamku] a=15,5/31 b=4*15,5/31-2 a=15,5/31 b=0
a) x+3y=3 x-y=5 x=3-3y x-y=5 x=3-3y 3-3y=5 x=3-3y -3y=5-3 x=3-3y -3y=2 |:(-3) x=3-3y y=-²/₃ x=3- 3*(-²/₃) y=-²/₃ x=3-(-2) y=-²/₃ x=5 y=-²/₃ b) 2x-y=10 x+5y=-17 -y=10-2x |:(-1) x+5y=-17 y=-10+2x x+5y=-17 y=-10+2x x+5(-10+2x)=-17 y=-10+2x x-50+10x=-17 y=-10+2x 11x=33 |:11 y=-10+2x x=3 y=-10+2*3 x=3 y=-4 x=3 d) 4a-2=b 3a+7b=1,5 b=4a-2 3a+7b=1,5 b=4a-2 3a+7(4a-2)=1,5 b=4a-2 3a+28a-14=1,5 b=4a-2 31a=15,5 |:31 b=4a-2 a=0,5 b=4*0,5-2 a=0,5 b=0 a=0,5
