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1. If one solution of the equation 3x^2 -8x+2k +1 is seven times the other . Find the solutions and the value of K .
2. For what value of K to the zeros of polynomial x^2 -5x+k are differ by 1
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Answered by
7
(1)
Given f(x) = 3x^2 - 8x + 2k + 1.
On comparing with ax^2 + bx + c + d, we get
we get a = 3, b = -8, c = 2k + 1
Now,
Let one of the zero be a.
Given that one of the zeroes is seven times the other. = > 7a.
= > we know that sum of zeroes = -b/a
a + 7a = -8/3
8a = 8/3
a = 1/3 ----- (1)
Therefore the other zero is 7a = 7(1/3)
= 7/3.
= > Also, the product of zeroes = c/a
a * 7a = 2k + 1 /3
1/3 * 7/3 = 2k + 1/3
7/9 = 2k + 1/(3)
2k + 1 = 7/3
2k = 7/3 - 1
2k = 4/3
k = 2/3.
(2)
Let a, b be the zeroes of the polynomial x^2 - 5x + k.
On comparing with ax^2 + bx + c, we get
a = 1, b = -5, c = k.
We know that sum = -b/a
= > a + b = 5/1
= > a + b = 5 ------ (1)
We know that product = c/a
= > ab = k/1
= > ab = k. ------ (2)
Now,
Given that they differ by 1.
= > a - b = 1. ------ (3)
On solving (1) & (3), we get
a + b = 5
a - b = 1
-------------
2b = 6
b = 3.
Substitute b = 6 in (1), we get
= > a + b = 5
= > a + 3 = 5
= > a = 2.
Substitute a = 2, b = 3 in (2), we get
= > 2 * 3 = k
k = 6.
Therefore the value of k = 6.
Hope this helps!
Given f(x) = 3x^2 - 8x + 2k + 1.
On comparing with ax^2 + bx + c + d, we get
we get a = 3, b = -8, c = 2k + 1
Now,
Let one of the zero be a.
Given that one of the zeroes is seven times the other. = > 7a.
= > we know that sum of zeroes = -b/a
a + 7a = -8/3
8a = 8/3
a = 1/3 ----- (1)
Therefore the other zero is 7a = 7(1/3)
= 7/3.
= > Also, the product of zeroes = c/a
a * 7a = 2k + 1 /3
1/3 * 7/3 = 2k + 1/3
7/9 = 2k + 1/(3)
2k + 1 = 7/3
2k = 7/3 - 1
2k = 4/3
k = 2/3.
(2)
Let a, b be the zeroes of the polynomial x^2 - 5x + k.
On comparing with ax^2 + bx + c, we get
a = 1, b = -5, c = k.
We know that sum = -b/a
= > a + b = 5/1
= > a + b = 5 ------ (1)
We know that product = c/a
= > ab = k/1
= > ab = k. ------ (2)
Now,
Given that they differ by 1.
= > a - b = 1. ------ (3)
On solving (1) & (3), we get
a + b = 5
a - b = 1
-------------
2b = 6
b = 3.
Substitute b = 6 in (1), we get
= > a + b = 5
= > a + 3 = 5
= > a = 2.
Substitute a = 2, b = 3 in (2), we get
= > 2 * 3 = k
k = 6.
Therefore the value of k = 6.
Hope this helps!
siddhartharao77:
:-)
Answered by
6
Heya....frst answer is dis....
Hope helps...
@skb
Hope helps...
@skb
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