If 2 is a zero of polynomial 4y2-6y-k, find the value of k. Also find the other zero.

2 is zero of polynomial p(y) = 4y2 - 6y - k 
P(2) = 4(2)2 - 6(2) - k [Substituting y = 2]
4(4) - 6(2) - k = 0
16 - 12 - k = 0
4 - k = 0
k = 4

Now putting value of k = 4 in equation
4y2 - 6y - 4 = 0
4y2 - 8y + 2y - 4 = 0         [Factorising: -8y * 2y = -16 and -8y + 2y = -6y]
4y(y - 2) + 2(y - 2) = 0
(y - 2) (4y + 2) = 0
y- 2 = 0 4y + 2 = 0
y = 2 and y = -2/4 = -1/2

Other zero is -1/2



 

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