f.4 a math
2006-10-30 5:14 am
if the roots of the equation 2x^2+6x+m = 0 differ by 5,find the real value of m
回答 (3)
2006-11-07 3:03 am
YOU ARE THE BEST, GUTTVENN!
2006-10-30 5:27 am
sun of roots = -a/b
so, sum of roots = -6/2 = -3
Let a root be a, and the other root be (a - 5)
i.e, a + (a - 5) = -3
2a = 2
a = 1
so , the roots are 1 or (1 - 5)= -4
product of roots = c/a
so, product of roots = m/2
i.e, (1)(-4) = m/2
m = -8
so, sum of roots = -6/2 = -3
Let a root be a, and the other root be (a - 5)
i.e, a + (a - 5) = -3
2a = 2
a = 1
so , the roots are 1 or (1 - 5)= -4
product of roots = c/a
so, product of roots = m/2
i.e, (1)(-4) = m/2
m = -8
2006-10-30 5:22 am
X1 = -2/4 + root(36-8m)/4
X2 = -2/4 - root(36-8m)/4
X1 - X2 = 5
5 = 2*root(36-8m) / 4
10 = root(36-8m)
100 = 36 - 8m
64 = -8m
m = -8
X2 = -2/4 - root(36-8m)/4
X1 - X2 = 5
5 = 2*root(36-8m) / 4
10 = root(36-8m)
100 = 36 - 8m
64 = -8m
m = -8
收錄日期: 2021-04-25 16:24:56
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https://hk.answers.yahoo.com/question/index?qid=20061029000051KK05212