2b
|
21x - 32 = 5x - 8y
||
5x - 6y = y - 9x
|
21x - 32 = 5x -8y |-5x
16x - 32 = - 8y |/(-8)
"" -2x + 4 = y ""
| in ||
5x-6*(-2x+4) = (-2x+4)-9x
5x+12x-24 = -2x+4-9x
17x-24 = 4-11x |+11x
28x-24 = 4 |+24
28x = 28 |/28
"" x = 1 ""
x = 1 in |
-2*1+4 = y
-2+4 = y
2 = y
prüfe
5*1-6*2 = 2-9*1
5-12 = 2-9
-7 = -7
3a |
4x+2y = 2 |/2
2x+y = 1 |-2x
y = 1-2x
||
-9x+3y = 33 |+9x
3y = 33+9x |/3
y = 11+3x
| = ||
1-2x = 11+3x |+2x
1 = 11+ 5x |-11
-10 = 5x |/5
"" -2 = x ""
x=-2 in |
y = 1-2*(-2)
y = 1+4
"" y = 5 ""
prüfe
5 = 11+3*(-2)
5 = 5
3b
|
35x-(10y-87) = 10-(32y+20x)
35x-10y+87 = 10-32y-20x |+10y
35x+87 = 10-22y-20x |+20x
55x+87 = 10-22y |-10
55x+77 = -22y |/(-22)
(-55/22)x+(77/-22) = y
"" -2,5x-3,5 = y ""
||
24x-(16y-15) = 10y-(15x-2)
24x-16y+15 = 10y-15x+2 |+15x
39x-16y+15 = 10y+2 |+16y
39x+15 = 26y+2 |-2
39x+13 = 26y |/26
"" 1,5x+0,5 = y ""
|=||
-2,5x-3,5 = 1,5x+0,5 |+3,5
-2,5x = 1,5x+4 |-1,5x
-4x = 4 |/(-4)
"" x = -1 ""
x=(-1) in ||
1,5*(-1)+0,5 = y
-1,5+0,5 = y
"" -1 = y ""
prüfe
1,5*(-1)+0,5 = -1
-1,5+0,5 = -1
-1 = -1
4a
|
5x-y = 14
||
-5x-16 = -6y |+6y
-5x-16+6y = 0 |+16
-5x+6y = 16
|+||
5x-y = 14
-5x+6y = 16
------------
5y = 30 |/5
"" y = 6 ""
y=6 in |
5x-6 = 14 |+6
5x = 20 |/5
"" x = 4 ""
prüfe
5*4-6 = 14
20-6 = 14
14 = 14
4b
|
(x+3)²-2y-x² = 2x+y+16
x²+6x+9-2y-x² = 2x+y+16 |-2x
4x+9-2y = y+16 |+2y
4x+9 = 3y+16 |-16
4x-7 = 3y
||
4(x-y)-(3x-5y) = 7
4x-4y-3x+5y = 7
x+y = 7 |-y |-7
x-7 = -y |*3
3x-21 = -3y
|+||
4x-7 = 3y
3x-21 = -3y
---------
7x-28 = 0 |+28
7x = 28 |/7
"" x = 4 ""
x=4 in ||
4*4-7 = 3y
16-7 = 3y
9 = 3y |/3
"" 3 = y ""
prüfe
4*4-7 = 3*3
16-7 = 9
9 = 9