Odpowiedź :
a) 2x-2y=7
4x+3y=21
2x=7+2y
4x+3y=21
x=3,5+y
4x+3y=21
x=3,5+y
4(3,5+y)+3y=21
x=3,5+y
14+y+3y=21
x=3,5+y
4y=7 /:4
x=3,5+y
y=1,75
x=3,5+1,75
y=1,75
x=1,75
y=1,75
4x+3y=21
2x=7+2y
4x+3y=21
x=3,5+y
4x+3y=21
x=3,5+y
4(3,5+y)+3y=21
x=3,5+y
14+y+3y=21
x=3,5+y
4y=7 /:4
x=3,5+y
y=1,75
x=3,5+1,75
y=1,75
x=1,75
y=1,75
2x-2y=7
4x+3y=21
2x=7+2y/2
4x+3y=21
x=3½+y
4x+3y=21
x=3½+y
4(3½+y)+3y=21
28/2+4y+3y=21
x=3½+y
4y+3y=21-14
x=3½+y
7y=7/7
y=1 podstawiamy teraz za y czyli do :
x=3½+1
x=4½
y=1
Pani powyzej nie pomnożyła dobrze w nawiasie:))
4x+3y=21
2x=7+2y/2
4x+3y=21
x=3½+y
4x+3y=21
x=3½+y
4(3½+y)+3y=21
28/2+4y+3y=21
x=3½+y
4y+3y=21-14
x=3½+y
7y=7/7
y=1 podstawiamy teraz za y czyli do :
x=3½+1
x=4½
y=1
Pani powyzej nie pomnożyła dobrze w nawiasie:))
2x=7+2y/:2
x=7+y
4(7+y)+3y=21
28+4y+3y=21
7y=21-28
7y=-7/:7
y=-1
x=7-1
x=6
x=7+y
4(7+y)+3y=21
28+4y+3y=21
7y=21-28
7y=-7/:7
y=-1
x=7-1
x=6