if the roots of the equation 2x^2+6x+m = 0 differ by 5,find the real value of m
2006-10-29 16:14:24 · 3 個解答 · 發問者 youlikeido 3 in 科學 ➔ 數學
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2006-11-06 14:03:00 · answer #1 · answered by 英王的教室 7 · 0⤊ 0⤋
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
2006-10-29 16:27:09 · answer #2 · answered by ? 2 · 0⤊ 0⤋
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
2006-10-29 16:22:34 · answer #3 · answered by ? 7 · 0⤊ 0⤋