Równania kwadratowe.
Mysza: Rozwiąż równanie.
3x2+1=7x
5x2=2−2x
5x2=8x−5
Anonim:
1) 3 x
2 + 1 = 7 x
3 x
2 − 7 x + 1 = 0
Δ = b
2 − 4a*c = (−7)
2 − 4*3*1 = 49 − 12 = 37
√Δ =
√37
| | − b − √Δ | | 7 − √37 | |
x1 = |
| = |
| |
| | 2 a | | 6 | |
| | − b + √Δ | | 7 + √37 | |
x2 = |
| = |
| |
| | 2 a | | 6 | |
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2)
5 x
2 = 2 − 2x
5 x
2 + 2 x − 2 = 0
Δ = 4 − 4*5*(−2) = 4 + 40 = 44 = 4*11
√Δ =
√4*11 =
√4*
√11 = 2
√11
| | − 2 − 2√11 | | − 1 − √11 | |
x1 = |
| = |
| |
| | 10 | | 5 | |
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3)
5 x
2 = 8 x − 5
5 x
2 − 8 x + 5 = 0
Δ = (−8)
2 − 4*5*5 = 64 − 100 < 0 − brak pierwiastków.
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