9x^2 +30x + 25+ -14
更新1:
but the answer is no real roots,( 9-5/3 +-√14/3 i)
F.4 Maths quardradic equations
回答 (2)
2013-09-04 2:58 am
✔ 最佳答案
Let me help you this time.9x² + 30x + 25 = -14
9x² + 30x + 39 = 0
3x² + 10x + 13 = 0
x = [-10±√(10²-4*3*13)]/(2*3)
x = [-10±√(100-156)]/6
x = [-10±√(-56)]/6
x = [-5±√(-14)]/3
x = [-5±√(14)i]/3
2013-09-03 8:51 pm
9x^2 +30x + 25 -14 =0
9x^2 +30x + 11=0
(3x-1)(3x+11)=0
x=1/3 or x=-11/3
2013-09-03 13:02:05 補充：
equation must have "="
9x^2 +30x + 11=0
(3x-1)(3x+11)=0
x=1/3 or x=-11/3
2013-09-03 13:02:05 補充：
equation must have "="
收錄日期: 2021-04-20 14:23:02
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https://hk.answers.yahoo.com/question/index?qid=20130903000051KK00063