Mila:
2x + lyl = 3
lxl − 2y = 3
Metoda graficzna
1) 2y=|x|−3
| 1 | | 3 | |
y= |
| |x|− |
| niebieski wykres |
| 2 | | 2 | |
| 3 | |
|y|=−2x+3 i −2x+3≥0⇔x≤ |
| |
| 2 | |
y=−2x+3 (0,3), (1, 1)
x=1, y=−1
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Metoda algebraiczna:
1) y≥0
2x+y=3
|x|−2y=3
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y=−2x+3
|x|−2*(−2x+3)=3
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|x|+4x−6−3=0 i
|x|+4x=9
x≥0
| 9 | | 9 | |
5x=9, x= |
| i y=−2* |
| +3<0 nie odpowiada zał. |
| 5 | | 5 | |
−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
lub
2)
y<0
2x−y=3
lxl − 2y = 3
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y=2x−3
|x|−4x+6=3
|x|−4x=−3
x≥0
x−4x=−3
x=1
y=−1
====
lub
y<0 i x<0
y=2x−3
−x−4x=−3
−5x=−3
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odp. x=1 i y=−1
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