Odpowiedź :
x+3y=12
2x-y=3
x=-3y+12
2*(-3y+12)-y=3
x=-3y+12
-6y+24-y=3
x=-3y+12
-7y=-24+3
x=-3y+12
-7y=-21 /: (-7)
x=-3y+12
y=3
x=-3*3+12
y=3
x=3
y=3
2x-y=3
x=-3y+12
2*(-3y+12)-y=3
x=-3y+12
-6y+24-y=3
x=-3y+12
-7y=-24+3
x=-3y+12
-7y=-21 /: (-7)
x=-3y+12
y=3
x=-3*3+12
y=3
x=3
y=3
x+3y=12
2x-y=3
x=12-3y
2×(12-3y)-y=3
24-6y-y=3
-6y-y=3-24
-7y=-21/÷(-7)
y=3
x=12-3×3
x=12-9
x=3
x=3
y=3
2x-y=3
x=12-3y
2×(12-3y)-y=3
24-6y-y=3
-6y-y=3-24
-7y=-21/÷(-7)
y=3
x=12-3×3
x=12-9
x=3
x=3
y=3